How to sign a PDF attachment and send it back in Gmail
Save the attachment, sign a separate PDF copy and check which file you attach before returning to the email conversation.
Updated 2026-10-26
To sign a PDF attachment and send it back in Gmail, download the PDF, add your signature in a PDF tool, save the edited copy and attach that copy to your reply. Check the saved file before attaching it. The incoming email still contains the original attachment.
If the message instead contains a link to a particular signing service, follow that requested process. The steps below are for a PDF file you can download and return.
Download the attachment you were asked to complete
Open the message in Gmail on your computer. Hover over the PDF attachment and choose its download control. Google's attachment instructions explain that the file is saved to your device; your browser's download settings determine the folder.
Open the file and read the instructions. Check that it is the expected document and that all necessary pages are present. If the message contains several attachments, choose the PDF the sender asked you to complete.
Keep an untouched copy. For example, you could keep "form-original.pdf" and later save "form-signed.pdf". Use names that help you distinguish your files.
If downloading is unavailable, ask the sender for the intended way to complete the document. Gmail's confidential mode can prevent downloads, and a link may lead to a different workflow.
Add the signature to the local PDF
You can use Sign PDF to add a visible electronic signature and text to a PDF in Chrome. Its store listing describes local processing, drawing or uploading a signature image, reviewing multiple pages and downloading the edited PDF.
- Open Sign PDF and choose Select Files, or drag the downloaded PDF into the extension.
- Go to the page that needs your signature.
- Draw the signature or add an image of your signature, then place it on the requested line.
- Add your name, date or other required text with the text tool.
- Review all pages that require an entry and select Download.
Use the drawn signature guide for pen controls, or the signature image guide if you already have an image. The result of this workflow is a visible electronic signature, not a certificate-based digital signature.
Check the copy outside the editing view
Open the downloaded result in a PDF reader. Inspect the completed fields and the signature placement. Compare the page count with the original and read the small text around each addition.
If you downloaded several attempts, choose one checked copy and give it a distinguishable name. A filename containing "signed" is only a label; opening the file is how you confirm that it contains your changes.
Saving the result on your computer does not replace the attachment in the incoming Gmail message. Sign PDF prepares the file; you still need to choose it in Gmail.
Attach the checked file to your reply
Return to the relevant conversation and open a reply. Check the recipients, especially if the conversation includes several people.
Select Attach in the reply box, choose the checked PDF from your computer and select Open. Wait for the attachment to finish loading, then compare the displayed filename with the copy you reviewed.
Google notes that original attachments are not automatically included in a reply. Including the original attachment, where that option is available, would not select your newly signed file. Choose the new copy yourself.
Google's sending instructions explain attaching files and size limits. For personal Gmail accounts, the total size of all attachments in one message must fit within 25 MB; work or school limits depend on the administrator. Gmail can replace an oversized attachment with a Drive link, so check the finished message if the file is large.
Make one last version check before sending
Read the message with its attachment in place. Does it name the right file and go to the intended recipients? Have you attached an old attempt or the untouched original alongside the finished copy?
Keep the original and checked PDF until the recipient has the document they need. If you find an error before sending, correct the PDF, review the new output and replace the attachment in the reply.
If you replace the attachment after an edit, wait for the new file to finish loading. Check its displayed name once more before sending.