Looking for a theme

I am looking for a theme in which clients can log in, create an account, upload a project, such as sketches, PDF files, a piece of text, etc. (construction assignments). Once these files have been uploaded, contractors, who also log in as a contractor, should see these assignments and get them out of the system.
Is there a theme that I can use where people can create accounts and upload / download documents?

Example site:
werkspot . nl/
klussersvinden . nl/

Thanks loads!
edit: deleted the links, as they create backlinks

edit2: I have found the WPtheme of Klussersvinden . nl, its named Overstrap.
So anything in that range would be amazing!