Exporting

Every object in a Project can be saved to a separate file.
Saving an object to an separate file is known as exporting.
To export an object (File > Export) or (Ctrl + E).
You will get a dialog box asking for the filename.
A copy of the file is then moved. The original file is not moved.

Userforms

When you export a Userform any code associated with that userform will also get exported.
.frm - this is a text file that contains the userform's VBA code and textual layout,
.frx - this is a binary companion file that stores all the non-code parts of a VBA UserForm.