Adobe Sign integration in to PHP Portal

Hi

I am a small freelance developer and I work for a company who ask their employees to upload timesheets weekly using a PHP web portal.  The documents are stored on the server and opened by an Administrator in the Administrative Portal - also written in PHP.  The company have asked me to find a way for these documents to be signed electronically each time they are opened by the Administrator - but they want this to be within the current workflow/portal.  Is this something Adobe sign could do?

Thanks in advance for your help.

Jo