Sweep
Select the profile sketch, then point at the path sketch above and press Enter.

The profile travels along the path and sweeps a body: a tube, a handrail, a cable duct, a seal around an outline.
Two sketches, not one
The profile and the path are different sketches and usually lie in different planes: the profile across, the path along. It is convenient to build them so that the start of the path lies in the plane of the profile.
What can go wrong
- The path turns tighter than the profile allows. If the turn radius is smaller than the profile size, the body intersects itself and the operation fails. Increase the radius or shrink the profile.
- An open path is normal; a closed one gives a ring.