From the time they separate to when they meet, Alice has had less time than Bob. She has had less time to do stuff, like ageing, writing a diary or watch movies.
As to what would twins see if they looked at each other, the answer depends on the specifics of the trajectory that Alice takes.
Let’s assume that Alice only accelerates to turn around once she is far enough and she wants to come back. While she is coasting at constant velocity in interstellar space, Bob would see her moving in slo mo.
(To see this, consider Alice having a computer program that emits a laser flash towards Bob every second. Bon can observe that. You know that every second on the spaceship is more than a second long as seen from Bob’s point of view, by time dilation. So he receives a flash every 1.2 seconda for example. But say that computer is also playing music, and Alice is dancing to that music. If she is keeping rhythm, she is synchronised with the laser flash, so if Bob could see her, he would actually see her moving in slow mo!)
But by special relativity, Bob is moving at constant speed in Alice’s frame, so she would see him moving in slo mo.
If that sounds paradoxical, and that is why this is called the Twin Paradox. The reason its not contradictory, and why it’s not actually a paradox, is that when Alice turns on her thrusters to accelerate herself to come back to Earth, she will slow down even more from Bob’s point of view. And she would see Bob speed up.