Software
Design a customer document portal around the missing item
A portal does not help much if it simply moves an email attachment into another folder. Its value is showing which document is needed, why it is needed and what happens after it arrives.
Name the requirement
A Colombian service organization may request different material for different projects. Give each required item a clear description, accepted formats and a responsible reviewer. Avoid collecting identity or financial documents merely because the system can store them.
Separate uploaded from accepted
A file may upload successfully and still be unreadable, outdated or the wrong document. Show whether it is awaiting review, accepted or needs replacement. A replacement request should explain what the customer can correct without revealing internal comments.
Plan access and expiry
Decide who may see each project, when access ends and what happens to completed records. A shared link with no expiry may be convenient but inappropriate for sensitive material. Your organization and advisers should establish data responsibilities before implementation.
Test a wrong file, a replacement, a reviewer absence and a customer who belongs to two projects. The OWASP file-upload guidance describes technical controls that need implementation-specific review. A customer portal project should include the staff review workflow as well as the upload screen.