I am working on a Layout and I want to connect two circles with lines. I notice that when I draw circles, a layer will appear in the Contents pane when I click in the layout and I can draw the circle just fine. When I select the line tool and click in the layout, a layer does not appear. I can draw the line all over the place, but I have no ability to complete my line. I can only hit escape to exit the drawing mode and that gets rid of what I have drawn.
ArcGIS Pro v2.9.1
A line can consist of more than 2 points, or vertices. When using the line tool a single click of the left mouse button places a point of the line. Double clicking the mouse completes the line.
Since a circle can be defined by its center (first click) and a radius (mouse drag) completion can be indicated by depressing the mouse button.
The Freehand line tool provides an experience similar to drawing a circle. The drag of the mouse inserts the needed vertices of the line. Depressing the mouse button completes the line. Since the line is being drawn "freehand" style it most likely will not be straight.
For more information please see the help topic Work with graphic elements in a map.
Hope this helps,