Use the Parameters selection level to access the PRS Parameters rollout which provides tools for creating and deleting keys. PRS stands for the three basic transform controllers: Position, Rotation, and Scale.
To create a PRS transform key:
Select an object in the viewports.
Drag the time slider to the frame where you want to place a key.
On the
Motion panel, choose Parameters > PRS Parameters rollout.
Click one of the following buttons under Create Key PRS Parameters rollout:
Click Position to create a Position key.
Click Rotation to create a Rotation key.
Click Scale to create a Scale key.
If a particular Position, Rotation, or Scale controller doesn't use keys, then that button is not available under Create Key. For example, you can’t create Position keys if you're using a Noise Position controller.

Creates or deletes a move, rotate, or scale key at the current frame. These buttons become active or inactive depending on the existence of a key type at the current frame.
For example, if you're on a frame containing a Scale key, the Scale button is inactive in the Create column because a key already exists. At the same time, the Position and Rotation buttons are inactive in the Delete column because there are no keys of that type to delete.
Determines the contents of the Key Info rollouts that appear below the PRS Parameters rollout on the Motion panel.