What is this feature?

A minimal user interface simplifies how a word processing program is displayed by hiding all menus.

How do I use it?

The “Full screen” mode in Google Docs hides the many options displayed by the text editor (e.g., the toolbar) in order to reduce screen clutter and allow the user to just write. When the writing is done the screen can be switched back to including the editing toolbar.

The “Focus Mode” in Microsoft Word serves the same purpose. Upon completion of the text, “Focus Mode” can be turned off and all editing tools are once again available.

Both are examples of a “minimal user interface”.

How does it help? 

A minimal user interface helps the writer focus on the task at hand by reducing screen distractions.