modeling/skeletons/moving for games

hi, i’m modeling for a video game my class is making. i’m using blender, and i have a finished model- except i’m not sure how to put in a skeleton. i have a basic understanding of how to make a skeleton in blender, but i’m not sure how it will work once its in game. also, i’m not to sure about how i’m supposed to save it and what format it should be in.