Last Name

Hi po I just want to share & ask if pwede po bang e use yung last name nang tatay kahit di pa kasal?as long as ok namn sa tatay na gamitin ito?papayag po kaya hospital na aanakan or they need documets like marriage certfcate/doc.?(mas nauna kasi si baby but we are planning to get married this year namn ngkataon lg na ngkapandemic) thank you for answering 😊 God bless!