One of the things I love about FreeCAD is that there are many ways to solve a problem. In this demonstration I introduce 3 ways to extrude a face.
There are several name for "Extrude" in FreeCAD. Depending on which workbench you are starting from.
Part Design - Pad ( working with sketches )
Draft - Trim or Extend ( will work on any face or line )
Part - Extrude ( a sketch )
The different tools take differing approaches to the extrusion and have different parameter available.