How do I obtain full child custody in missouri if the father is completely willing to sign over his rights?

I am the mother of a newborn. The father wants nothing to do with the baby and I am not requesting any child support or anything from him. Do I need to go to court to obtain full custody or can he just sign forms over since he’s completely willing?

I would make sure this is absolutely what you want and make it legal, that way later on down the road he can’t come back on it