How can you create a 2D sketch on a planar face of a 3D model?

Creating a 2D sketch on a planar face of a 3D model in SolidWorks is accomplished by selecting the face and utilizing the "New Sketch" tool. This method allows you to establish a sketch directly on the surface of the selected face, enabling you to create geometry that is precisely aligned with the 3D model.

When you select the face and initiate a new sketch, SolidWorks automatically orients the sketching plane to match the selected face, streamlining the design process. This is particularly useful for creating features such as extrudes, cuts, or other modifications that need to relate directly to the geometry of the model.

The other methods suggested either do not exist within the software or do not accurately represent how to initiate a sketch on a 3D model. The right-click option generally provides access to various features, but the correct and straightforward way to create a sketch in this context is indeed through the direct selection of the face followed by the "New Sketch" tool. Thus, the chosen answer reflects the most efficient and correct technique in SolidWorks for starting a 2D sketch on a planar face.