In animation, tweening is short for in-betweening, which is the process of drawing the frames that transition one keyframe - or major pose - to another.
In Adobe Animate, tweening refers to the several automated processes of creating those in-betweens.
Classic Tweening and Motion Tweening are two important functions to utilize in puppet animation. Both options utilize easing to time out the motions. Simply, this is the timing and spacing between each “frame” of movement.
Classic Tweens turn the frames purple. You can add individual keyframes along a Classic Tween, allowing you to utilize single frames in the frame picker.
To see the “path” of the motion, you have to use the onion skin and lengthen its range.
Easing options are located in the Properties panel under the Frame tab.
Motion Tweens turn the frame yellow.
You can add new points of motion along your Motion Tween, but you can't switch between single frames in the frame picker. Looping animations within symbols can be used.
Motion Tweens create a dotted orange line on the stage that represents the path of motion. You can use the selection tool to curve the line or move the individual points.
Easing is accessed by double-clicking the Motion Tweened frame. This will open a graph menu showing the X and Y movement of the symbol over time.