The three ways to sign a PDF

You can sign a PDF in three ways: draw your signature directly in the document using your mouse or trackpad, insert an image of your handwritten signature, or use a digital certificate that creates a legally binding signature. Which one you choose depends on whether the signature needs to be legally enforceable or just visually present, and whether you're signing alone or collecting signatures from others.

Most people use the first two methods for everyday documents — contracts you're keeping for your records, forms you're submitting to a business, or PDFs you're sending to colleagues. The third method, a digital certificate, is what banks and government agencies require when a signature has legal weight and must be verified as authentic.

Your PDF reader or editor determines which methods are available to you. Adobe Acrobat Reader (the free version) lets you draw or insert a signature image. Adobe Acrobat Pro and other paid editors add digital certificate signing. Free online tools like Smallpdf, ILovePDF, and Sejda offer drawing and image insertion but rarely offer certificate signing.

Key Takeaways

  • Drawing your signature directly in the PDF works in Adobe Acrobat Reader and most PDF editors, and requires only your mouse or trackpad.
  • Inserting a scanned or photographed image of your handwritten signature looks more natural and takes the same number of steps as drawing.
  • Digital certificate signatures create a legally verifiable record that the document came from you and has not been altered since you signed it.
  • Collecting signatures from multiple people requires either a tool designed for that purpose (like DocuSign or Adobe Sign) or sending the PDF back and forth between signers.

Drawing your signature directly in the PDF

Open the PDF in Adobe Acrobat Reader, then click the Sign button in the toolbar on the right side of the screen. Select Add Signature, then choose Draw. A signature box will appear in your document — click inside it and draw your signature using your mouse or trackpad. When you're satisfied, click explore.

The drawn signature will appear in the PDF at the size and position you chose. You can move it, resize it, or delete it before saving. Once you save the file, the signature becomes part of the document. This method works in Adobe Acrobat Reader (free), Adobe Acrobat Pro, and most other PDF editors including Preview on Mac and many free online tools.

Drawing with a mouse or trackpad is awkward for most people — your signature will look shaky or oversimplified. If the document is for your own records or an informal submission, this is fine. If you want the signature to look like your actual handwriting, use an image instead.

Inserting an image of your signature

Create an image of your signature first by writing your name on white paper with a pen, photographing it with your phone, and saving the photo to your computer. Alternatively, use a drawing app or tablet to create a digital signature and save it as an image file (PNG or JPG work best). Crop the image so it shows only your signature with minimal white space around it.

Open the PDF in Adobe Acrobat Reader and click Sign on the right toolbar. Select Add Signature, then choose Image. Navigate to your signature image file and select it. A signature box will appear in your document — click inside it to place the image. Resize and position it as needed, then click explore.

This method produces a signature that looks like your actual handwriting because it is your actual handwriting. The image is embedded in the PDF, so the signature stays in place even if the file is opened on another computer. Most PDF editors support image insertion, including free online tools.

Using a digital certificate for legally binding signatures

A digital certificate signature creates a cryptographic record proving that you signed the document and that no one has altered it since. This is required for contracts, loan documents, and government filings where the signature's authenticity must be verifiable. You obtain a digital certificate from a certificate authority — common providers include Sectigo, GlobalSign, and DigiCert. The certificate costs money (typically $100 to $300 per year) and requires identity verification.

Once you have a certificate installed on your computer, open the PDF in Adobe Acrobat Pro. Click Sign, then Add Digital Signature. Select your certificate from the list, draw or insert your signature image as the visual representation, and click the location where you want it to appear. The signature is now legally binding and can be verified by anyone with the certificate authority's public key.

Most people do not need a digital certificate. Banks and government agencies will tell you if one is required. If you're signing a contract with a business and they don't specify, a drawn or image-based signature is sufficient.

Collecting signatures from multiple people

If you need others to sign the same PDF, you have two options: use a signature collection tool designed for that purpose, or send the PDF back and forth between signers.

Signature collection tools like DocuSign, Adobe Sign, and HelloSign let you upload a PDF, specify where each person should sign, and send signing requests to multiple recipients. Each person receives a link, signs the document in their browser, and the tool tracks who has signed and who hasn't. These services charge per document or per month. DocuSign and Adobe Sign are the most widely used and integrate with email and document storage services like Google Drive and OneDrive.

If you don't want to pay for a service, you can email the PDF to the first signer, ask them to add their signature using the methods above, save the file, and email it to the next signer. This is slower and creates multiple versions of the file, but it works for informal agreements or documents where the order of signatures doesn't matter legally.

Saving and sharing your signed PDF

After you add your signature, save the file by pressing Ctrl+S (Windows) or Command+S (Mac). Adobe Acrobat Reader will prompt you to save a copy with a new filename — this preserves the original unsigned PDF if you need it later. Choose a location on your computer and confirm the save.

You can now email the signed PDF, upload it to a website, or print it. The signature remains part of the document and will appear the same way on any device that opens the file. If you used a digital certificate, the signature's verification status will be visible to anyone who opens the document in Adobe Acrobat Pro or another tool that recognizes digital signatures.

If you need to add another signature to the same document later, open the saved file and repeat the signing process. You can have multiple signatures on one page, and they can overlap or be positioned separately depending on your needs.

Common problems and how to fix them

If your drawn signature looks too shaky or illegible, delete it and try again. Use slower, deliberate strokes rather than quick ones. If you're using a trackpad, consider using a stylus or switching to an image-based signature instead.

If your signature image appears blurry or pixelated, the original image file is too small or low resolution. Retake the photo or recreate the image at a larger size, then insert it again. A signature image should be at least 200 pixels wide to look clear when placed in a PDF.

If you cannot find the Sign button in your PDF reader, you may be using an older version of Adobe Acrobat Reader. read the latest version from Adobe's website. If you're using a different PDF reader, check whether it supports signature features — some free readers do not.

If you're trying to collect signatures from others and they report that they cannot sign, confirm that you're using a tool designed for multi-person signing (like DocuSign or Adobe Sign) rather than sending them a PDF file directly. Most people do not know how to add a signature to a PDF on their own.

Frequently Asked Questions

Is a signature I draw in a PDF legally valid?

A drawn or image-based signature is legally valid in most situations because it shows intent to sign. However, it does not prove you actually created it or that the document hasn't been altered. For contracts where authenticity must be verifiable, use a digital certificate signature instead.

Can I use the same signature image in multiple PDFs?

Yes. Save your signature image file and reuse it whenever you need to sign a PDF. You can insert the same image into as many documents as you want. This is faster than drawing your signature each time.

What if I make a mistake and sign in the wrong place?

Delete the signature by clicking it and pressing Delete, then add a new one in the correct location. You can undo and redo signatures as many times as you need before saving the file.

Do I need Adobe Acrobat Pro to sign a PDF?

No. Adobe Acrobat Reader (free) lets you draw or insert a signature image. You only need Acrobat Pro if you want to use a digital certificate signature or need advanced editing features.

Can someone forge my signature if I use an image?

Yes, if they have access to your signature image file, they could insert it into a PDF themselves. For documents where forgery is a concern, use a digital certificate signature instead, which creates a cryptographic record that proves you signed it.