Keyframe Editing - Premiere Pro
From Help Wiki
Keyframes can be used to change values over time for various effects.
A keyframe marks the point in time where you specify a value, such as spatial position, opacity, or audio volume. Values between keyframes are interpolated. To create a change in a property over time, you set at least two keyframes—one keyframe for the value at the beginning of the change, and another keyframe for the value at the end of the change.