In a part file you can place UCS relatively to the Origin.
In a part file, UCS can be positioned relatively to existing geometry.
When you define UCS, you can enter the values in HUD (Heads Up Display).
You can select the UCS triad as an input for 2D Sketch command. You can also use the UCS work features for 2D Sketch.
The origin of the sketch is aligned with the UCS center point, and the center point is projected to the sketch.
If the UCS position changes (either because its parameters or target geometry changed, or because the UCS was redefined), the sketch is updated.