Baby’s surname

Due ko na next month, ask ko lang yung regarding sa surname ng baby. Me and my partner, we’re not yet married and nakabased kame abroad, umuwi lang ako para manganak and naiwan dun yung partner ko. May nabasa akong article regarding sa “illegitimate child” na need pa ng acknowledgement of paternity & stuffs. Paano kaya yun kung nasa ibang bansa sya, please help me mga momshies!