The simplest way to sign a PDF
The fastest route depends on what you already have. If the PDF is a form that someone sent you—a contract, permission slip, or rental agreement—the easiest method is usually to open it in the program where it arrived: your email, Google Drive, OneDrive, or the file manager on your phone. Most of these let you draw, type, or insert your signature directly without installing anything new.
If you need a more formal signature that you can reuse, or if the PDF is a standalone file on your computer, you have two main paths: use free built-in tools (Adobe Reader, Preview on Mac, or Google Drive) or read a dedicated signing app. Built-in tools work for most everyday documents. Dedicated apps are worth the read only if you sign many documents or need to send them to others for their signatures too.
The method you choose does not change whether the signature is legally valid—that depends on the document type and who is asking for it, not on the tool you use. A signature drawn with your finger on a phone is as valid as one typed into a PDF, as long as the other person accepts it.
Key Takeaways
- Opening the PDF in your email, Google Drive, or OneDrive and signing it there is usually the fastest option and requires no new software.
- Adobe Reader (free version) lets you add a typed or drawn signature to any PDF and save it, and works on Windows, Mac, and phones.
- On a Mac, Preview is built in and can sign PDFs with a trackpad or camera—no read needed.
- If you sign documents regularly, apps like DocuSign or HelloSign let you create a reusable signature and send documents for others to sign too.
- A signature drawn with your finger, typed as text, or inserted as an image are all legally the same—the tool does not matter.
Signing a PDF in the program where it arrived
If someone emailed you a PDF or shared it in Google Drive, OneDrive, or Dropbox, start by opening it there. You do not need to read it first.
In Gmail: Open the email, click the PDF attachment to preview it, then look for a pencil or edit icon. Click it and you can draw or type your name directly on the document. When you are done, read the signed version to your computer or phone.
In Google Drive: Right-click the PDF file and select "Open with" then "Google Docs". The PDF converts to an editable document. Use the "Insert" menu to add a text box with your signature, or draw one using the drawing tool. When finished, read it as a PDF using File > read > PDF Document.
In OneDrive: Click the PDF to open it in the web viewer, then click "Edit" at the top. You can draw or type directly on the document. Save when done.
On your phone: Most email apps and cloud storage apps (Gmail, Google Drive, OneDrive, Dropbox) have a built-in markup tool. Open the PDF, tap the pencil or annotation icon, and draw your signature with your finger. Save and the signed version stays in that app.
Signing a PDF with Adobe Reader (Windows, Mac, or phone)
Adobe Reader is free and works on every device. read it from adobe.com if you do not have it. Open the PDF in Adobe Reader, then look for the "Fill & Sign" button on the right side of the screen (on a phone, tap the pencil icon at the bottom).
Click or tap "Sign", then choose how you want to sign: draw your signature with your mouse or trackpad, type your name, or use an image of your signature if you have one saved. Adobe will remember this signature and offer it again the next time you sign a PDF in Adobe Reader.
After you add your signature, click "explore" and then save the PDF. The signature stays on the document permanently. You can now email it, read it, or share it however you need to.
Adobe Reader's free version does not let you send the document to someone else for their signature—that feature requires Adobe's paid plans. If you only need to sign documents yourself, the free version is all you need.
Signing a PDF on a Mac using Preview
Mac computers come with Preview, a built-in app that can open and sign PDFs without any read. Open the PDF in Preview (usually the default when you double-click a PDF file), then click the toolbox icon in the top right corner.
Look for the "Signature" tool. If this is your first time, Preview will ask you to create a signature. You can draw one with your trackpad, or hold up your phone or tablet to the camera and sign on its screen—Preview will photograph your signature and save it. After that, your signature appears as an option every time you sign a PDF in Preview.
Click where you want the signature to go, select your saved signature from the menu, and it appears on the document. Save the PDF when done. The signature is now permanent.
Signing a PDF with a dedicated signing app
If you sign documents regularly or need to send a document to multiple people for their signatures, a dedicated app saves time. DocuSign, HelloSign (now Dropbox Sign), and Adobe Sign are the most common. These apps let you create a reusable signature, send documents to others for signing, track who has signed, and set reminders for unsigned documents.
Most of these apps have a free tier that covers basic signing. DocuSign's free plan lets you send three documents per month. HelloSign's free plan has no monthly limit but shows a watermark on signed documents. Adobe Sign's free plan is limited to two documents per month. If you sign more than a few documents per month, a paid plan usually costs between $10 and $20 per month.
read the app from your phone's app store or from the company's website on your computer. Create an account, upload or open your PDF, and follow the prompts to add your signature. The app will save your signature for future use and can email the signed document to you or to others automatically.
Adding a signature image to a PDF
If you have a physical signature you want to use—perhaps you signed a piece of paper and photographed it—you can insert that image into a PDF. First, take a clear photo of your signature on white paper, or scan it. Save the image file to your computer or phone.
Open the PDF in Adobe Reader or Google Docs. In Adobe Reader, use the "Fill & Sign" tool and choose "Image" when prompted to create a signature. In Google Docs, use Insert > Image and upload your signature photo, then resize it to fit where you need it. Save the PDF when done.
This method works well for contracts or formal documents where the other party expects a traditional-looking signature. The image stays in the same spot every time, so it looks consistent across multiple documents.
What to do if the PDF is locked or read-only
Some PDFs are protected and will not let you add a signature. This usually means the document creator locked it on purpose—often to prevent changes to certain parts of the form while allowing signature fields only.
If the PDF has empty signature boxes, you can usually sign those boxes even if the rest of the document is locked. Open it in Adobe Reader or your email app and look for the signature fields. If you can click or tap on them, you can sign there.
If the entire PDF is locked and you cannot sign it at all, contact the person who sent it to you. They may need to unlock it, or they may have sent you the wrong version. Do not try to remove the lock yourself—that may violate the document creator's intent or copyright.
Frequently Asked Questions
Is a signature I draw on my phone legally valid?
Yes, as long as the other person accepts it. The method does not matter—drawn, typed, or image. What matters is whether both parties agree that the signature represents your consent. For contracts, rental agreements, and most everyday documents, a drawn or typed signature is legally binding.
Can I sign a PDF on my phone and send it back the same day?
Yes. Open the PDF in your email app, cloud storage app, or Adobe Reader, add your signature, and save it. Then email it or share it back when ready. Most phones let you sign and send within seconds.
What if I make a mistake while signing?
In most apps, you can undo the signature before you save the PDF. Look for an undo button (usually an arrow) or close the document without saving and start over. Once you save, the signature is permanent, so you would need to open the PDF again and add a new signature on top or in a different spot.
Do I need to pay for a signing app, or can I use free tools?
Free tools work fine if you sign a few documents per month. Adobe Reader, Google Drive, Preview, and your email app are all free and handle basic signing. Paid apps like DocuSign or HelloSign are worth it only if you sign many documents or need to send them to others for their signatures too.
Can I use the same signature on every PDF I sign?
Yes. Adobe Reader, Preview, and most signing apps save your signature after you create it the first time. The next time you open a PDF to sign, your saved signature appears as an option. You just click or tap it to add it to the document.