About the rights of an illegitimate child

I am currently pregnant and is about to give birth anytime soon. The dad of the child and i are not married but he is willing to give support to the child. We talked about giving the child my last name (mother) then if we get married then the child to have the father's last name. But how does that work in the birth certificate? If he signs as the father will the child's name be automatically his last name or what. I really have no idea. Can he also just sign as the father? Does the child need the consent of the father in everything the child does since the father signed as the father? Hoping someone could help me.

Sa alam ko he is just acknowledging that he is the biological father. Optional na sa iyo kung gamitin ng anak mo ang family name ng father o hindi.

Sole parental authority and custody of the illegitimate child belongs to the mother.