How to Sign a PDF on Mac: Preview and Online Tools

You can sign a PDF on a Mac by using Preview: trackpad, camera, the iPhone/iPad method, or an online PDF editor. However, not all of these options guarantee high-quality signatures. Moreover, some tools are also complicated to use, as they require special knowledge or come with subscriptions that are too expensive.

Instead of using such tools, you can follow our steps to sign a PDF on a Mac with highly functional, reliable, and simple software. Let’s start!

Key Takeaways

The easiest way to sign PDFs on a Mac is to use the Preview camera, trackpad, and iPhone/iPad features.
You can also use the Markup tool on iPhone or iPad to sign PDFs without Preview and share them to your Mac device.
To further simplify the signing process, it’s recommended to utilize the pdf.net sign tool, which allows you to add digital signatures within minutes while keeping the highest security levels for your data and documents.
You may encounter issues when signing your PDFs on a Mac; for example, the signature may not save, or it may look messy, the signed PDF may become uneditable, and the file may significantly increase in size.

How to Sign a PDF on Mac with Preview: 3 Simple Methods

You can sign a PDF on Mac with Preview by using a trackpad or a camera. That said, let’s see how to use these options to sign PDFs with Preview.

#1. Sign PDF in Preview with Trackpad

The process of putting a signature on a Mac PDF consists of the following steps:

Find the PDF file you want to sign, right-click it, choose Open With, and select Preview.
Click the Markup button from the toolbar at the top.
Choose the Sign option.
Once you click on the Sign option, the ‘Trackpad’ option will be selected by default, and you should choose Click Here to Begin.
Use the trackpad to move your cursor and create a signature.
Preview will automatically add your signature, which you can insert into a document by clicking on it, to the Sign menu.
Clicking on the signature will allow you to resize it by dragging the edges inward or outward and position it where you want.
Select the File menu and click Save to finalize this process.

Still, filling in a PDF on a Mac using a trackpad can be tricky, as you have to create the entire signature in one take.

If you are not well-versed in using a trackpad with your finger to create handwritten signatures on a Mac, you can use a stylus if your model supports it. This tool functions as a pen and can help you sign your PDFs with precision to get clear and readable signatures.

#2. Sign PDF in Preview with Camera

If you’re looking for a way to sign a PDF on a Mac without a trackpad, you should use the built-in camera feature. Here are the steps:

Locate the file you wish to sign, right-click it, and open it with Preview.
Choose the Markup tool from the toolbar on the top right.
Click the Sign button.
From the drop-down menu, choose Camera.
Write your signature on a blank piece of paper and ensure that it is readable.
Move the paper close to the camera and wait until the program detects and renders it.
Once you are satisfied with the signature, click Done at the bottom-right.
Click the Sign button again to select the signature and move it to the document.
Place the signature, select File, and click Save to complete this process.

Still, adding a digital signature to a file in Preview on a Mac this way may be challenging because you need to avoid image artifacts or similar problems.

Your camera may have difficulties reading the signature due to lens scratches or bad handwriting. Plus, the lighting in your room has to be good for the auto-focus option to work correctly and for the camera to read your signature successfully.

If you experience difficulties with this option, you can still try other procedures for signing a PDF on a Mac.

#3. Sign a PDF in Preview Using iPhone & iPad

Here’s the complete process for signing a PDF in Preview using iPhone and iPad:

Open the file you want to sign in Preview on Mac.
Click the Show Markup Toolbar icon.
Click the Sign button and choose iPhone.
Use your finger on iPhone or the Apple Pencil on iPad to create a signature.
The signature will appear in the box, after which you should click Done to save it.
Click the Sign button to open the signature from your iPhone or iPad.
Click the signature, drag it to the document, position it where you want, and resize it if needed.
Select File and click Save to finalize the procedure.

This is one of the handiest ways to digitally sign a PDF on a Mac, as many users find it easier to create a signature on the iPhone screen instead of using a trackpad. Furthermore, if you’re on an iPad, you can use an Apple Pencil, which allows for stability and control during the process and makes natural-looking signatures.

In addition to using files from your drive, you can sign PDFs from an email. The process is simple—all you should do is open your email, find the file you want to sign, and click the Markup tool icon. This will open your email document, allowing you to sign it.

If, however, you want to add signatures straight from an iPhone or iPad, you can use the built-in Markup tool. Similar to Preview, the signing process with the Markup tool includes selecting the document, opening this tool, choosing the sign option, creating a signature, and saving your file. Once you are done, you can transfer PDFs from iPhone or iPad to a Mac.

How to Sign a PDF on Mac Online

You can sign a PDF on a Mac online with pdf.net. Our platform offers one of the fastest and easiest opportunities to sign a PDF online; all you have to do is take the following steps:

Open the website and click Sign on the web page’s header.
Click Choose file to upload your document manually, or drag it to the box that says Drop file here to sign.
Choose whether you want to type, draw, or upload the signature and click Place in PDF afterwards.
Position your signature in a document and adjust its opacity, resize, or rotate it according to your needs.
Click away to save the signature on your file and press the Download button in the top-right corner to save the PDF to your drive.

Our PDF-signing tool is available for all devices, regardless of the manufacturer or operating system. Also, thanks to the high cross-platform functionality we offer, you can easily share your documents with a single click after signing them.

The digital signatures on our platform are rather secure since they include audit trails, which you can use to detect any modifications.

Aside from signing, pdf.net offers other editing tools:

You can change the text in your document without formatting modifications
It allows you to convert your PDFs to Word or turn them into JPG files or any other well-known formats
You can merge your PDFs or split them for easier handling, etc.

6 Common Issues When Signing PDFs on Mac and How to Fix Them

Common issues when signing PDFs on a Mac include difficulties with adding and saving the signature in Preview, signed PDFs becoming uneditable, signatures not appearing in other PDF readers, and more.

That said, let’s examine the most frequent problems in more detail and how to fix them.

#1. Signature Not Saving in Preview

Typically, after you click Save in Preview, your signature should be embedded in the document, but that’s not always the case. Due to a temporary bug, Preview may not save the signature the way it should. In this case, we suggest restarting your Mac to hopefully resolve this issue.

If this doesn’t work, you may have to force the signature to flatten by clicking on File, then Print and Save as PDF. When you open your new PDF file, the signature should be there.

#2. Trackpad Signature Looks Messy

Creating a signature with a trackpad can be tricky since you have to do it all in one take. As a result, it may end up looking messy, unreadable, and unprofessional, which is not appropriate for certain kinds of documents.

You can avoid issues with the trackpad by simply opting for a different signing method, such as inserting an image or using the camera option to scan your handwritten signature from a piece of paper. We’ve described both methods above, so feel free to use the one that suits you best.

#3. Cannot Add Signature in Preview

If the signature is missing when you open Preview, that’s most likely because the Markup toolbar is hidden and you simply need to toggle it. You can do so by clicking the Markup icon or using the CMD + Shift + A shortcut. In either case, the toolbar with the Signature icon should show up.

However, in some cases, you may not be able to sign your document even when the Markup toolbar is available because the PDF is locked or read-only. Check the file info to see whether you have the necessary permissions to edit the file.

If none of this helps, you may be dealing with a temporary glitch. Restart your Mac and try again; this simple solution often works best.

#4. Signed PDF Becomes Uneditable

Sometimes, signing a PDF locks the document or at least certain fields in it and prevents further editing. This happens to protect the integrity of the document, but it may be inconvenient if you aren’t aware of that and still need to make changes.

So, before you sign a document, always make a copy that you can edit in case a digital signature locks it. Also, double-check that you’ve filled out all fields and made all the necessary adjustments.

#5. Signature Not Appearing in Other PDF Readers

If your signature appears in Preview but not in other PDF readers, the issue may be that it isn’t properly embedded into your document. The best solution is to flatten the PDF by using the Print and Save as PDF functions, as we discussed earlier.

#6. Large File Size After Signing

Adding your signature in Preview may result in an unusually large file, especially if you use the scanned image method. This may be inconvenient for sending the document; its size may end up being too large for an email.

The solution is fairly simple, though. All you need to do is open the document in Preview and click File and Export. When a new dialogue box appears, select the Quartz Filter option and then Reduce File Size. Check whether the text and images in the document still look good; if so, save the file, and you’ll see that its size is significantly smaller.

Final Thoughts

Signing PDFs on a Mac is possible with Preview in three ways (iPhone or iPad, trackpad, and camera). This gives you plenty of options to choose from, but some of these processes can be too complicated for some users or cause unexpected issues with your files.

If too many features or options confuse you or if you have safety concerns, we suggest you sign your PDFs with our online editor on any device or operating system. Our user-friendly platform lets you add digital signatures in several clicks and provides maximum protection during and after the signing process!

How to Sign PDF on Mac FAQs

#1. How do you write your signature on a Mac?

You can write your signature on a Mac using the Sign feature in Preview, which allows you to insert it with a trackpad, camera, iPhone, or iPad. Alternatively, you can use an online PDF editor that allows you to insert your signature with just a few clicks.

#2. Are digital signatures on Mac legally binding?

Yes, digital signatures on Mac are legally binding in many countries when they meet applicable laws (e.g., eIDAS, ESIGN). Besides representing an easier and more convenient option for many, these legal electronic signatures meet official standards and regulations just like physical ones.

#3. Can I sign secured or password-protected PDFs?

Yes, you can sign secured or password-protected PDFs, but only if you know the decryption password or the passcode that allows you to remove the signature or read-only restrictions.

#4. How do I sign a PDF if I’m not the only signer?

If you’re not the only signer, you sign a PDF using high-encryption tools such as pdf.net, which allows you to use a public key that only you and the other signer know. This prevents anyone else from accessing your document during the signing process.

#5. Can I automate my signature for batch documents?

Yes, you can automate your signature for batch documents. To do so, upload multiple PDFs to our website, create and add a signature, and select all or specific document pages on which you want to save your signature.

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