Filling AOS forms with Husbands last name

[flower777]

Hi all!
Im confused about filling the forms of AOS, i want to use my husbands last name, some people told me i can fill my new name on the forms, but they ask me my family name what this means my old name? or i can write my husbands last name there?
in EAD they just ask me my name so im gonna write here my new name, but in I-485 i just see family name.
Help please!!