Use the Level tool to define a vertical height or story within a building. You create a level for each known story or other needed reference of the building (for example, first floor, top of wall, or bottom of foundation).
To add levels, you must be in a section or elevation view. When you add levels, you can create an associated plan view.
Levels are finite horizontal planes that act as a reference for level-hosted elements, such as roofs, floors, and ceilings. You can resize their extents so that they do not display in certain views. For more information, see Datum Extents and Visibility.
You can hide level annotations after you add them. For more information, see About Hiding Elements in a View.