Exporting Folders for another Programmer in Cloud Storage

At first, sorry for my bad grammer!

I have a question:
A friend and I are trying to program a game. The problem is, that he can´t see my progress because the .umap file isn´t in the copies I´m sending him.
So he can only see the “starter Content Game Map”.

How is it possible for 2 different Unreal Accounts, to work together?

Please help me and thanks for the answers!