Menu: Geometry->Edit->Surface boolean op.
You need to select two 2D surfaces located in the XY plane (order is important when dealing with subtraction).
The valid surface boolean operations are:
- Union: Fuses two surfaces wherever they intersect to create a single, more complex surface.
- Intersection: Creates a surface based on the intersecting points of two separate surfaces.
- Subtraction: Negates a specific portion of a surface to create a hole or indentation.
- Subtraction and intersection: Creates the intersected and the substracted surface at the same time.