Guide
A Document is a Rich Text view object that lives in the Sidebar within one of your Spaces.
Alternatively, Documents can be associated with an entity in a given Database (provided the Database has the Documents field enabled - see Fields ).
Check out Rich Text for more details.
If you want to build a wiki, but not sure whether to use Documents or Document databases, check this community topic.
You can disable Documents and they will be hidden from UI everywhere. Navigate to Settings → General and find Disable documents option.
Choose your page width
Documents have three width modes, so they look good on any screen.
Narrow is best for reading. Lines are shorter and text is easier to follow.
Medium works well for most screens and everyday work.
Wide gives you as much space as possible. Handy for big tables or large monitors.
Try them out and pick the one that suits you.