There are several types of dimensions including height dimensions for cross sections and special dimensions in 3D.
For 2D representation there are additional display options available in the dimensions property dialog.
As default dimensions use their own units, it is therefore possible to work in meters in your planning and let the dimensions display the values in millimeter.
Text, and the values as text, can be separated from a dimension and changed later on without changing the length of a dimenion chain.