i want the bullet not only hlcan hit body and head but can hit arm and leg
is there any better way to put the collider other than put the collider on every bone?
Creating gameobjects with a collider and attaching it to individual body parts is probably the easiest method. Although you could look into tagging each body part differently (e.g. head) and having a raycast determine what body part has been hit by reading its tag.
I’m sure there are more ways but I’ve never done it before so I’m just making an educated guess. If this is your first game I would try to keep things simple.