If you turn on Set IK/FK Keys in the options window for Animate > Set Key > , you can subsequently use Animate > Set Key as an alternative to Animate > IK/FK Keys > Set IK/FK Key.

If you use Animate > Set Key for an object that’s not an IK handle, a joint controlled by an IK handle, or an object connected to an IK handle, the Set IK/FK Keys option is ignored.

If you turn on Set Full Body IK keys in the options window for Animate > Set Key > , you can subsequently use Animate > Set Key or the Set Key hotkey (s key) as an alternative to Animate > Set Full Body IK Keys.