How to Sign PDFs on iPhones: 2 Safe & Secure Methods

You can sign PDFs on iPhones by using the built-in Markup tool that comes with iOS or pdf.net for a browser-based experience. Both methods allow you to add a signature directly from your phone, but they suit slightly different needs.

If you just have to sign a document from the Files, Mail, or Messages app, you can add your signature in seconds with Markup. pdf.net, on the other hand, is more useful if you need to upload files from different sources, adjust placement more precisely, or manage multiple documents at once.

In this guide, we will walk you through the specific steps for each approach. You will also find practical tips for signing PDFs on iPhones here, as well as some advice on how to troubleshoot common issues.

Key Takeaways

• You can sign PDFs on an iPhone by using Markup or an online signing tool.
• Markup is a built-in iOS feature that you can activate in apps like Files, Notes, and Photos.
• Pdf.net is an online editor that works on any mobile browser as long as you have a reliable Internet connection.
• To ensure your signed PDF is legal and professional, consider creating a master signature to reuse and using a stylus for thinner and more controlled strokes.
• Don’t forget to check that your signature is placed properly on a signature line, proportionately sized, and clearly accurate after signing.

2 Simple Ways to Sign PDFs on iPhones

There are two ways to electronically sign PDFs on iPhones, and that is using the built-in Markup tool from iPhone or an online PDF editor, such as pdf.net. Here’s how the two compare:

#1. Use the Markup Tool

Markup is a built-in iOS feature you can use to add electronic signatures to your PDFs. It was originally introduced in iOS 9 for Mail, but has been integrated with Files, Photos, and Messages since iOS 10.

Using this tool is ideal if you are looking for a way to sign documents on an iPhone for free; all you need to do is:

1. Open your PDF.
2. Click the Signature icon (the last one from left to right).
3. Click the plus sign.
4. Choose Add signature.
5. Sign your name using your finger.
6. Click Done to insert it.

After you create a signature, your iPhone will automatically save it so that you can reuse it next time, which is handy if you handle many PDFs daily. However, your iPhone needs to be secure to prevent others from using your signature without permission.

This tool is also convenient because you won’t have to browse the App Store and download anything; it is already available for you to use as long as you have iOS 10 or later. It can save you a lot of time, especially if you are signing PDFs on the go, and you don’t need to worry about paying for any subscription plans.

Markup isn’t just an iPhone PDF signer, though. You can also use it to add text or draw on your PDF. With the former, you can customize the fonts, sizes, and alignment, and with the latter, you can change the stroke thickness, color opacity, and color shades.

#2. Use Our Online PDF Sign Tool

pdf.net has an intuitive Sign PDF tool you can use to create digital signatures on your iPhone and apply them to documents. Here are the steps you will need to take:

1. Open the website.
2. Click the hamburger menu in the top-right corner.
3. Press Sign.
4. Click Choose PDF to sign and upload your document.
5. Select Choose files.
6. Tap the PDF you need to sign and click Open.
7. Add your signature using one of three methods available.
8. Tick Save for future use to store a consistent version of your signature.
9. Click Place in PDF.

Our online PDF sign tool is fully browser-based, meaning you can use it on your iPhone through Safari, Chrome, etc. It will work seamlessly as long as you have a reliable Internet connection.

To safeguard your documents, pdf.net uses HTTPS connections and automatically deletes files shortly after processing. You can also protect your PDFs by applying a password; plus, we use AES-128 encryption, a symmetric algorithm, to embed the content and PDF metadata in the file’s structure.

Using our tool is an excellent way to sign PDFs on iPhones, but that is not all you can do with it; we offer many other tools for preparing and polishing your PDFs.

For example, you can create fillable forms, contracts, or invoices and then share them to request signatures. Your recipients can easily open the shared PDF link, add their signatures, and return the document to you using Share PDF.

You can choose from three pricing plans:

1. $0.95 for 14 days of limited access
2. $1.95 for 14 days of full access
3. $24.95 per month for annual access

4 Valuable Tips for Signing PDFs on iPhones

Keep these four tips in mind when signing PDFs on your iPhone:

#1. Ensure Your Signature Is Clear and Accurate

For an electronic signature to be legally recognized, it must clearly represent your identity and show your intent to sign. That said, a messy scribble or partially cut-off signature can raise questions.

To make sure your signature on an iPhone is clear and accurate, you need to sign slowly and deliberately; use your finger or a stylus to write at a moderate pace. If the signature looks distorted, it is best to undo it and try again. After inserting your signature, you can drag the corners to resize it proportionally.

#2. Use a Stylus for More Precision

It is easy to make shaky strokes when signing with your finger; a stylus can make your signature look more natural and professional.

Before you begin, ensure the stylus is designed to support iPhones. A few common options are Fiftythree Digital Stylus, Adonit Pixel, and MoKo Universal Active Stylus Pen. If your stylus has a battery, confirm it is charged so it won’t lag or cause your strokes to break.

Next, find a stable surface to rest your palm on, as this helps you maintain consistent pressure to make steadier strokes. If there is a signature box on the PDF, don’t try to squeeze your signature into that tiny space. Instead, you should sign freely outside, then resize and reposition it to fit the box.

#3. Keep a Saved Digital Signature for Repeated Use

Re-signing your name every time you open a PDF is tedious and can lead to inconsistencies. These not only make your documents appear unprofessional but also raise doubts. It is much better to take the time to create and save a single master signature to reuse. Both Markup and pdf.net allow you to do this.

However, you must be more careful about your iPhone’s security. Since your signature is stored and available for you to apply to PDFs whenever you want, anyone who can access your iPhone can do so without your permission.

To reduce this risk, you should enable Face ID or Touch ID. Studies comparing facial and fingerprint recognition with traditional passwords and PINs have found that biometric methods generally provide stronger security than short numeric passcodes, particularly 4-digit ones.

Even if you choose to use passcodes, go with one that’s longer than 4 digits. Research comparing 4- and 6-digit passcodes in shoulder surfing attacks, for example, found that 6-digit ones were much harder for attackers to guess from observations.

You should also avoid saving your signature on shared devices, and be cautious about leaving your phone unattended. Additionally, you can consider setting your phone to lock automatically after a short period of inactivity for an extra layer of security.

#4. Check the Signed Document Before Sending

Don’t send your PDF right after applying your signature, but take a couple of seconds to review that everything is good to go.

First, zoom in to check that your signature is not hovering above the signature line or overlapping surrounding text. Your signature should look proportional to the rest of the document. If it appears oversized or stretched, you can adjust it by dragging the corners.

Then, you need to verify that you have signed all the fields required in your PDF. It is common to miss additional signature boxes on later pages, so go through each page carefully.

Troubleshooting Tips for Signing PDFs on iPhones

If you are having trouble signing a PDF on your iPhone, don’t panic; most issues can be addressed easily.

• The Markup option is missing. If you are previewing the PDF from a browser or a link, editing tools may not appear. So, save the PDF to the Files app. When you open it, you should be able to find the pen icon and access Markup.
• The signature is distorted after resizing. This tends to happen when you drag from one side. You need to use the corner handles to stretch all sides evenly if you want to maintain the correct proportions.
• The stylus is not responding. Is it fully charged and connected? If you can’t get your device working, check the battery levels and settings, then try to reconnect it.
• Document won’t allow editing. The PDF may be locked or flattened. In this case, you can try opening it in a dedicated reader or request an editable version from the sender.

Sign PDFs Easily on Your iPhone

Need to sign a document using only your iPhone? pdf.net offers a fast and convenient way to sign PDFs online. You can upload your PDF, create your signature in seconds, place it accurately, then download and send it back. With our online tool, signing PDFs is fast, simple, and secure, wherever work takes you!

Final Thoughts

Now that you know how to sign PDFs on an iPhone, you won’t have to worry about leaving documents piled up when you are out. You can apply your signature easily by using Markup or pdf.net. Applying the tips we provided above will help you ensure your signed PDFs are always legal and professional!

How to Sign a PDF on iPhones FAQs

#1. How do I write on a PDF on my iPhone?

You can write on a PDF on your iPhone by using pdf.net; our tool works on all mobile browsers and offers a range of tools you can take advantage of. Plus, you can edit existing text, add new text boxes, or select a marker or highlighter to write on your PDF.

#2. How do I add a signature to a PDF on an iPhone without an app?

You can add a signature to a PDF on an iPhone without an app with pdf.net. Another option is to leverage Markup, the native feature available for iPhones with iOS 10 onwards.

#3. Is signing PDFs on an iPhone legally binding?

Signing PDFs on an iPhone is legally binding if you clearly intend to sign, consent to conduct business electronically, and ensure the signed record is properly retained in accordance with the ESIGN Act.

#4. Can I sign multiple PDFs at once on an iPhone?

No, you can’t sign multiple PDFs at once on an iPhone by using Markup or pdf.net. Each document must be opened and signed individually, but you can speed up the process by saving your signature and reusing it.

#5. How do I remove or edit a signature on an iPhone?

You can remove or edit a signature on an iPhone by using either Markup or pdf.net. Simply open the signed PDF, tap your signature, and choose the option to edit or remove it. However, note that if you drew your signature, you can resize or recolor it, but you can’t adjust individual strokes.