You can upload multiple documents with the standard upload document functionality as long as you use the correct associations in the domain model. It is of course always the intention that you use a 1-* association so that you can link multiple files to the context object.

Once you have done the upload you can iterate (loop) over these documents with a microflow so that you can check the name of each document. You can then associate that document object to an object of another type of entity (in this case the User) as long as you have an association between that other entity and your file document entity.