Changing daughters last name.

Long story short my daughters father didn’t want to be in picture so I gave her my boyfriends last name. We were together for 5 years but we broke up. My daughter has his last name and we already disestablished paternity. Court didn’t mention anything about changing her last name . So my question is I want to give her my last name, would I have to go file paperwork at court? Or how does that work. Thank you in advance