Draw Curve mode

This mode lets you draw various curve shapes.
Menu path: Mode -> Draw Curve.
Action category: Drawing.
Default key: Ctrl-Alt-D.
Additional actions: Increase Sudivision Level, Decrease Sudivision Level.

You can activate this mode by pressing Ctrl-Alt-D (default key).
You can use the side panel or "Increase Sudivision Level" and "Decrease Sudivision Level" actions to control how detailed the curve is: