How to E-Sign a PDF Legally in India (and Why Pasting a Signature Image Is Not Enough)
Pasting an image of your signature into a PDF is not an electronic signature under Indian law. How to sign a PDF so it is legally recognised, the three methods that work, what the signed file should contain, and how to check a signed PDF you receive.
Search "how to sign a PDF" and the top answers show you how to draw or paste a signature image. That produces a picture, not a legally recognised electronic signature, and it offers no proof of who signed or whether the document changed afterwards. This guide explains what Indian law treats as an electronic signature, the three ways to sign a PDF that meet it, what the signed file should contain, and how to verify a signed PDF someone sends you. Position as of October 2026.
Why an image is not a signature
Section 2(1)(ta) of the Information Technology Act, 2000 defines an electronic signature as authentication of an electronic record by a technique specified in the Second Schedule, including a digital signature under section 3. A pasted image is not a Second Schedule technique. It can still be evidence that someone agreed (section 10A says electronic contracts are not unenforceable for being electronic), but it does not satisfy a legal requirement for a signature under section 5, it does not identify the signer, and it does not detect later changes to the PDF.
Three methods that work
1. Digital Signature Certificate (DSC). With a Class 3 certificate on a USB token and signing software (or a platform), the PDF is signed cryptographically: the file's hash is signed with your private key and the certificate is embedded. Any later change invalidates the signature. Best for your own authorised signatories and statutory filings.
2. Aadhaar eSign. Through an e-signature platform acting as an Application Service Provider, you authenticate with an OTP or biometric via UIDAI; a one-time certificate is issued and the PDF's hash is signed. Legally an electronic signature under section 3A and the Second Schedule. Best for counterparties, employees and anyone without a token.
3. Platform signature with audit trail. You sign on a platform that verifies your email or phone, records the document hash, timestamps, IP and the signing events, and seals the final PDF. Not a Second Schedule signature, so not for documents where the law requires a signature, but proportionate for consents and low-value acknowledgements, with evidence far stronger than an image.
What the signed PDF should contain
- The visible signature block with signer name, date and method.
- The embedded cryptographic signature (DSC or eSign) that a PDF reader can validate, or, for a platform signature, a completion certificate appended with the audit trail summary.
- The document hash recorded at signing.
- For chargeable agreements, the e-stamp certificate as the first page (stamp before signing: section 17, Indian Stamp Act, 1899).
Keep the audit trail with the file. Since 1 July 2024, electronic records are proved under section 63 of the Bharatiya Sakshya Adhiniyam, 2023, which requires a certificate describing the record and the system that produced it; the audit trail is what that certificate describes.
How to check a signed PDF you receive
- Open it in a PDF reader that validates signatures; look for the signature panel showing the signer's certificate and "document has not been modified since this signature was applied".
- Check the certificate issuer is a Certifying Authority licensed by the CCA (for DSC or eSign).
- Compare the document hash in the completion certificate with the file, if the platform provides a verification page.
- Confirm the signer is the person with authority (a resolution or authority letter for a company).
- Confirm the e-stamp certificate matches the instrument and state.
If the "signature" is only an image and there is no embedded signature or audit trail, treat the document as unsigned for anything that matters and ask for proper execution.
Step by step: signing a contract PDF properly
- Finalise the document; lock the content.
- Generate and attach the e-stamp certificate if the agreement is chargeable.
- Send the signing request through a platform that supports DSC and Aadhaar eSign; specify the method per signer.
- Each signer authenticates and signs; the platform records the audit trail.
- Download the completed PDF with embedded signatures and the completion certificate; store both.
Where Legatio fits. Legatio produces signed PDFs with embedded DSC or Aadhaar eSign signatures, a completion certificate and a verification page, and keeps the audit trail for the section 63 certificate. The legal distinction between an image and a signature applies to every tool.
Position stated as of October 2026. General information, not legal advice.