How to Add Your Signature to a PDF File

The fastest way depends on what you already have

You can add your signature to a PDF in three main ways: draw it directly in the PDF using your mouse or trackpad, insert a scanned image of your handwritten signature, or use a typed signature that looks like handwriting. Which method works best depends on whether you have a scanner, whether the PDF needs to look formal, and what software you already own.

Most people use free tools like Adobe Acrobat Reader (the basic version) or Preview on Mac, which let you draw a signature without buying anything. If you need something that looks more official or works across many documents, paid options like Adobe Acrobat Pro or specialized signature software offer more control and faster workflows.

Key Takeaways

Adobe Acrobat Reader's free version lets you draw, type, or upload a signature image directly into any PDF without installing extra software.
On Mac, the Preview app has a built-in signature tool that captures your signature from your trackpad or webcam in seconds.
If you scan your handwritten signature as an image file, you can insert it into most PDFs using either Acrobat Reader or your operating system's built-in tools.
Typed signatures work in PDFs but look less personal — use them only when the document doesn't require a handwritten appearance.
Once you create a signature in Acrobat Reader or Preview, the software saves it so you can reuse it on future documents without redrawing it.

Using Adobe Acrobat Reader (Windows and Mac)

Open the PDF in Adobe Acrobat Reader, then click the Fill & Sign tool in the right panel. If you don't see it, click Tools at the top, then select Fill & Sign. Click the signature icon (it looks like a pen) in the toolbar that appears.

You now have three options. To draw your signature with your mouse or trackpad, click Draw, then use your cursor to write your name in the box that appears. To use a typed signature, click Type and enter your name — Acrobat Reader will format it to look like handwriting. To insert a scanned image of your signature, click Image, then browse to the file on your computer.

Once you've created your signature, click where on the PDF you want it to appear. The signature will be placed at that spot. You can resize it by dragging the corners. When you're done, save the PDF using File > Save or Save As. Acrobat Reader remembers your signature, so the next time you open the Fill & Sign tool, your signature will appear as an option to reuse.

Using Preview on Mac

Open the PDF in Preview (the default Mac PDF viewer), then click Tools in the menu bar and select Annotate. Click the signature icon in the toolbar — it looks like a cursive line. A window will appear asking how you want to create your signature.

Choose Trackpad to draw your signature using your trackpad, Camera to hold up a handwritten signature to your webcam and let Preview capture it, or Image to upload a scanned signature file. The trackpad method is fastest if you're comfortable drawing with your trackpad; the camera method is fastest if you have a physical signature you want to photograph.

Once Preview captures your signature, click on the PDF where you want it to appear. The signature will be placed there. You can resize it by dragging the corners. Save the file using File > Save. Like Acrobat Reader, Preview stores your signature and offers it as a quick option on future documents.

Scanning and uploading a signature image

If you want to use your actual handwritten signature, scan it on a flatbed scanner or photograph it with your phone camera. Save the file as a JPG or PNG image on your computer. Make sure the signature is clear, centered in the image, and has a white or transparent background — crop out extra blank space around the edges.

Open your PDF in Acrobat Reader or Preview, then use the image upload option in the signature tool (described above) to insert the file. The signature will appear as an image layer on top of the PDF, so it won't change if the document is edited. This method looks the most authentic because it's your actual signature, but it also means the signature is identical every time — some formal documents require a unique signature for each signing.

When to use typed signatures

Typed signatures are fastest when you need to sign many documents quickly and the recipient doesn't require a handwritten appearance. They work well for internal company documents, informal agreements, or situations where speed matters more than formality. Most PDF tools offer several handwriting-style fonts, so a typed signature doesn't look like plain text.

Avoid typed signatures for legal documents, contracts, or anything that might be challenged later — handwritten or scanned signatures carry more weight in disputes because they're harder to forge. If you're unsure whether the document needs a handwritten signature, ask the recipient before you sign.

Saving and reusing your signature

Both Acrobat Reader and Preview automatically save any signature you create. The next time you open the signature tool, your saved signature appears as an option — you don't have to redraw or re-upload it. This saves time if you sign many documents.

If you want to create multiple signatures (for example, a formal signature and a casual one), you can do that in most tools. Each signature is stored separately, and you can choose which one to use when you sign a document. If you ever want to delete a saved signature, look for a settings or preferences menu in the signature tool — most programs let you remove old signatures from the saved list.

Frequently Asked Questions

Can I sign a PDF on my phone or tablet?

Yes. Adobe Acrobat Reader has a mobile app for iPhone, iPad, and Android that includes the Fill & Sign tool. Preview is available on iPad. Both work the same way as the desktop versions — you can draw, type, or upload a signature image. Some phones also let you use your finger to draw directly on the screen, which feels more natural than using a mouse.

What if I make a mistake while drawing my signature?

Most tools let you clear and redraw before you place the signature on the PDF. Once the signature is placed, you can usually delete it and create a new one. In Acrobat Reader, right-click the signature and select Delete. In Preview, click the signature and press Delete. Then create a new signature and place it again.

Is a signature in a PDF legally binding?

That depends on the laws in your location and the type of document. Many jurisdictions recognize digital signatures as legally valid for contracts and agreements. However, some documents — like wills or notarized papers — may require a handwritten signature or a certified digital signature from a trusted provider. If you're signing something important, ask the recipient whether a PDF signature is acceptable.

Can someone else use my saved signature?

Only if they have access to your computer or device. Saved signatures are stored locally on your machine, not in the cloud. If you share a computer, anyone with access to your user account can use your saved signatures. If that's a concern, delete your saved signatures from the tool's settings and create a new one each time you sign.

What file format should I use for a scanned signature?

JPG and PNG both work in Acrobat Reader and Preview. PNG is better if your signature has a transparent background (no white box around it), because it preserves that transparency. JPG is fine if your signature has a white background. Make sure the file is at least 150 pixels wide so it doesn't look blurry when you resize it on the PDF.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.