Click a tool in the Mode ribbon group.You can also right-click an
empty area of the Design window and select Sketch Mode, Section
Mode, or 3D Mode from the context menu, or press K
(for Sketch mode), X (for Section mode), or D (for 3D
mode).If you are sketching, you can also click Return to 3D mode in the Sketch plane mini-toolbar.
If you are switching from 3D mode to one of the other modes, select a plane
to sketch on or create the cross-section.When you select an origin
object or its center and click Sketch mode, the sketch plane is aligned to
the origin object's XY axis.
in the Sketch plane mini-toolbar.