Updating a PDF document throughout the process and across various apps

Updating a PDF document throughout the process and across various apps

I have a document (.pdf) that is submitted by customers, referred to during our work process, and then is ultimately signed by our company and returned to the customer. We are currently uploading it to CRM, Projects, and then into Sign. We would like to upload and access it in these three apps, and have the ability to add text boxes to it in Projects (for our notes) and ultimately sign it in Sign. Is there a suggested workflow you would recommend for this? Currently we have 3 different copies in the 3 apps. We are not able to type over or sign the pdf in Projects. Would like to make it fully editable in Projects. Any suggestions?