How to check the authenticity of documents

Hi,

Good day!

This may sound a bit of a noob question but I’m a bit of hurry to sum things up so I need some help here.

I want to check the authenticity of documents by verifying their embedded cryptographic signatures or upload detached signatures for document signed after they were stored.

Can someone please guide me how? I searched around but can’t find anything related to my concern.

Thank you.