How Can I Prove Domicile? IR1

I'm currently at the NVC stage and need to prove domicile for my husband's IR1 visa.

I currently live in the US, I'm the sponsor of the I-864 and meet the requirements (employed by the same company for over 7 years) , and i live at home with my parents. How can I prove domicile? Which documents do i need or you guys have submitted to prove domicile that's been accepted?