If a signature is not validated in a PDF, we see Validity unknown with a question mark. You need to validate the signature to make it valid.

This tutorial shows you how to enable and validate Digital Signature for PDF files in the Microsoft Edge browser. You can also view digital signatures in Edge.

Aadhaar card signature verification, validation, change: Open the 'EAadhaar'.pdf file on your system where you had saved it after downloading it from the official website of UIDAI Aadhaar- https ...