How to cut and trim 3D surfaces and 3D solids in cad, thank you.

This is called Boolean operation in CAD.

Is to subtract a circular entity from a square entity.

Right-click any toolbar and select the Entity Edit toolbar.

The first three icons are Boolean operations.

The first is set (that is, addition).

The second is the difference set (that is, subtraction).

The third is union (that is, overlapping parts are reserved).