The simplest way to sign a PDF
You can add your signature to a PDF in three main ways: draw it directly in the PDF using your computer or phone, insert an image of your handwritten signature, or type your name in a signature-style font. The method you choose depends on what the document requires and what device you have available.
If the PDF already has a signature field (a box or line marked for signing), most PDF readers will let you click it and sign right there. If not, you can still add a signature anywhere on the page. The fastest route for most people is using free software that comes with your device — Adobe Reader on Windows or Mac, Preview on Mac, or the built-in PDF app on your phone.
Key Takeaways
- Adobe Reader (the free version) lets you draw, type, or insert an image signature directly into any PDF without paying for Adobe Acrobat.
- On Mac, the Preview app can add signatures without any additional software — just use your trackpad or a photo of your handwritten signature.
- On iPhone or Android, your phone's built-in PDF reader or a free app like Adobe Reader Mobile lets you sign by drawing on the screen.
- Signature fields in the PDF (marked boxes or lines) make signing faster because the software knows exactly where your signature should go.
- An image of your handwritten signature works for any PDF and looks more official than a typed name, but takes a few extra steps to set up.
Adding a signature in Adobe Reader on Windows or Mac
Open your PDF in Adobe Reader (the free version, not Acrobat). Look for a "Sign" button or option in the toolbar — on Windows it is usually in the top menu, and on Mac it appears in the right sidebar. Click it, then choose how you want to sign: draw with your mouse or trackpad, type your name, or use an image of your signature.
If you choose to draw, a signature box will appear on the page. Use your mouse or trackpad to write your signature, just as you would on paper. If the result does not look right, click "Clear" and try again. Once you are satisfied, click outside the box to place it on the document. You can then move it around by clicking and dragging, or resize it by pulling the corners.
To use a typed signature, select the "Type" option and enter your name. Adobe will show you several signature fonts to choose from. Pick the one that looks most like a signature and click to place it on the page. To use an image of your signature, you will need to have already photographed or scanned your handwritten signature and saved it as a file on your computer. Select "Image," browse to that file, and click to place it on the PDF.
Signing a PDF on Mac using Preview
Mac's built-in Preview app can add signatures without any additional software. Open your PDF in Preview, then click the "Markup Toolbar" button (it looks like a toolbox) in the top right. A row of tools will appear at the bottom of the window.
Click the signature icon (it looks like a pen) in that toolbar. If this is your first time signing in Preview, you will see a dialog asking how you want to create your signature. You can draw it with your trackpad, use your iPhone or iPad camera to photograph a handwritten signature, or use an existing signature you have already saved. Choose your method, complete the signature, and click "Done."
Now click on the PDF where you want the signature to appear. Preview will place it there, and you can resize or move it by clicking and dragging. Once you are happy with the placement, save the PDF by pressing Command+S or going to File > Save.
Signing a PDF on your phone
On iPhone, open your PDF in the built-in Files app or in Adobe Reader (available free from the App Store). In Adobe Reader, tap the pencil icon at the bottom, then tap "Sign." You will see options to draw your signature with your finger, type your name, or use an image. Draw directly on the screen, then tap "Done" to place the signature on the page.
On Android, open your PDF in Adobe Reader or your phone's default PDF viewer. Look for a pencil or edit icon, then select the signature tool. Draw your signature with your finger on the screen. Once placed, you can move it around by tapping and dragging. Save the file when you are finished.
Signing on a phone works best when you have a stylus or when the document does not require a perfectly neat signature. If you need a more polished look, consider signing on a computer instead.
Using an image of your handwritten signature
If you want your signature to look handwritten but do not want to draw it each time, create an image file of your signature once and reuse it. Sign your name on a piece of white paper with a dark pen, then photograph it with your phone or scan it with a scanner. Save the image to your computer.
Open your PDF in Adobe Reader or Preview. In Adobe Reader, click Sign, then choose "Image" and browse to your signature file. In Preview on Mac, click the signature icon in the Markup Toolbar, then choose "Use Signature" and select your saved image. Click on the PDF to place it. You can now use this same image signature on any PDF without redrawing it.
When photographing your signature, use good lighting and hold the paper flat and straight. Crop the image afterward so it shows only your signature with a small border of white space around it. This makes it easier to place on documents and looks more professional.
Saving your signed PDF
After you add your signature, you must save the file to keep the changes. In Adobe Reader on Windows or Mac, go to File > Save or press Ctrl+S (Windows) or Command+S (Mac). The program will save the signature directly into the PDF file.
In Preview on Mac, press Command+S or go to File > Save. You will see a dialog asking where to save the file and what to name it. You can overwrite the original file or save it with a new name — saving with a new name is safer if you want to keep an unsigned copy.
On your phone, Adobe Reader and most PDF apps will save automatically, but check the app's menu to confirm. Look for a "Save" or "Done" button, or check your app's settings to see where files are being stored.
What to do if the PDF has signature fields
Some PDFs come with pre-made signature fields — boxes or lines marked specifically for signing. These are common in contracts, forms, and official documents. When you open such a PDF in Adobe Reader or Preview, the signature field will be highlighted or outlined.
Click directly on the field to sign it. The software will open a signature dialog and automatically place your signature in that exact spot when you are done. This is faster and more precise than manually placing a signature anywhere on the page. If the document has multiple signature fields (for example, one for you and one for a witness), you can sign each field separately.
Some signature fields are marked as required, meaning you cannot save the document without signing them. Others are optional. The document itself will usually indicate which fields must be signed.
Frequently Asked Questions
Can I sign a PDF on my computer without installing any software?
Yes. If you use Mac, Preview is already installed. On Windows, Adobe Reader is free to read and works for signing. Both are built-in or free options that do not require a paid subscription. You do not need Adobe Acrobat Pro to add a signature to a PDF.
Does my signature need to look exactly like my real signature?
No. A signature on a PDF is a digital mark, not a legal document in most cases. It shows that you have reviewed and approved the document. For informal documents, a typed name or straightforward mark is fine. For contracts or official paperwork, a handwritten-looking signature (drawn or photographed) looks more professional, but the exact appearance matters less than the fact that you signed it.
What if I make a mistake while drawing my signature?
Most PDF software lets you click "Clear" or "Undo" to erase the signature and try again before you place it on the page. Once the signature is placed on the document, you can usually delete it by right-clicking and selecting "Delete" or by selecting it and pressing the Delete key. Then you can draw a new one.
Can I use the same signature image on multiple PDFs?
Yes. Once you save an image of your signature, you can insert it into any PDF. In Adobe Reader, choose "Image" when signing and select your saved signature file. In Preview, use "Use Signature" to select a saved image. This saves time if you sign many documents.
Is signing a PDF legally binding?
That depends on the document and your location. A signature on a PDF shows you have reviewed it, but whether it is legally binding depends on the type of document, the laws in your area, and whether both parties agreed to sign digitally. For contracts or official documents, check with the other party or a lawyer about what signature method they require.