Sketches define the sizes and shapes of profiles, paths, and hole placements.
Profiles, paths, and hole centers are consumed when you create features with them. The Sketch tab contains commands to work with sketches.
You can edit any sketch before, or after you use it in a feature. You can change dimensions, trim or extend curves, add sketch fillets, add or delete constraints, drag sketch curves to change sketch shape, and control the position of sketches.