Multiple animations for one Character

How can I play multiple animations for my characters or NPCs simultaneously? For example, the player runs and fires a rifle. How can I play run animation and aim animation at the same time?

I believe you’re looking for blending animations. This is quite basic and common topic - you cant find it in documentation and via simple searching.

For example:
UE4 official tutorials

Maybe he have two different models/mesh and then put it inside the character blueprint class and then play two animation at the same time.

Actually, i’m questioning if that’s possible, pls answer, thx

it is theoretically possible but each would need to be a skeletal mesh and would need to be running their own anim bp. its possible but not really the best solution in most cases. for a basic character that you want to be doing two animations at once there are better ways to do it like blending.