Default main toolbar > Select And Manipulate button
Quad menu > Common quadrant > Manipulate mode
The Select And Manipulate command lets you edit the parameters of certain objects, modifiers, and controllers by dragging "manipulators" in viewports.
Note: Unlike Select And Move and the other transforms, this button's state is nonexclusive. As long as Select mode or one of the transform modes is active, and Select And Manipulate is turned on, you can manipulate objects. However, you must turn off Select And Manipulate before you can select a manipulator helper.
These are the features that have manipulators:
Spotlights (both Target and Free): see Spotlight Parameters
In addition, you can add these custom manipulators to your scene:
See also