Do I need to install software to sign a PDF?

No. The entire process happens in the browser — on desktop and mobile. The signer does not even need a zipzipdoc account.

What if a signer rejects the document?

The signer can decline with a comment. You receive a notification and can revise and resend the PDF.

Is the signed PDF protected from edits?

Yes. Every signed PDF is cryptographically locked — any change after signing is detectable and the signature is flagged as invalid.

Guides

How to sign a PDF online

Sign any PDF document electronically in under 3 minutes — no printing, scanning or postage needed.

Easy 3 min 4 steps

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Steps

Step-by-step walkthrough

1

Upload your PDF to zipzipdoc

Log in to app.zipzipdoc.com and click New document. Upload an existing PDF or let the AI generate a new one from your brief.
2

Add signers

Enter the name and email of each signer. You can set a signing order — e.g. client first, then yourself.
3

Send for signing

Click Send. Each signer receives a unique link by email. Signing happens directly in the browser, no installation required.
4

Download the signed PDF and audit trail

Once all parties have signed, you receive an email with the final PDF and audit trail — proof of time, IP address and identity of every signature.

Frequently asked questions

Yes. The eIDAS Regulation (No 910/2014/EU) recognises electronic signatures as legally binding in all EU countries. For most commercial documents (NDAs, contracts, invoices) an electronic signature is fully sufficient.