UX for managing documents as attachments in a desktop application [on hold]

I am currently working on a web application that manages letting agreements where the user should be able to upload / attach one or more documents to the letting agreement, for example a signed contract (word or pdf) or drawings/images (jpg). The agreement mainly handles resources (buildings/areas), the letting period and prices, bue the user also has a physical and signed contract. Now the issue is how to present and enable easy handling of these documents after they have been uploaded. Should the user be able to rename the actual filenames, add a new name in addition to it the file name (is it neccessary?)? The amount of documents that can be added is limitless, but normally be between 1-3 documents. Does anyone have any good ux tips for managing documents in a web application, where document archiving is not the focus of the application. Any input is much appreciated.