There are two different types of custody in Pennsylvania. Legal custody and physical custody.
Legal custody is the right to make decisions for one's child. Where he or she will go to school, whether the child will have a surgery, which church to go to. Those are all legal custody decisions. Most custody arrangements maintain a 50/50 legal custody situation so that both parents must agree before major life changes in the child's life can take place.
Physical custody is where the child actually resides on a daily basis. This can be structured differently depending on the needs of the parents.