I haven’t seen my child in almost two years. But I still have pay child support every month. How do I go about getting a custody agreement

if you cannot reach an agreement with mom, you have to file a petition with the court and ask for partial custody or visitation.  there is nothing else - either you reach an agreement with mom or you ask the court to decide when and how often you will see your child. each county in PA has a specific procedure that you have to follow when you file that kind of a petition so make sure you either hire a loweyr to help you, or be very careful about following your county's rules. if you don't follow the rules, your case will be dismissed and you will have to start all over - a waste of time and money.