The Ellipse tool in the Sketch > Create panel lets you create ellipses as sketch geometry or construction geometry in an active sketch in Fusion.
You can use the following command to create ellipses in an active sketch:
The Ellipse command creates an ellipse defined by a center point, the major axis, and a point on the ellipse.
You click to place the center point of the ellipse, place the second point to define the first axis, then place the third point that lies along the ellipse.