Dynamic Input in the sketch environment provides a Heads-Up Display (HUD) interface near the cursor to help you keep your focus in the sketching area. Dynamic Input is enabled for the Line, Circle, Arc, Rectangle, and Point sketch commands.
When Dynamic Input is on, value input fields near the cursor display information that dynamically updates as the cursor moves. You can enter values in the input boxes, and you can switch between the input fields to change values.
When you are satisfied with your dimension values for the sketch, they are automatically applied to the sketch element. The function that automatically creates and places sketch dimensions in Dynamic Input is called Persistent Dimensions.