This means the county where the Decedent lived and considered their primary home address before they died. Domicile for estate tax purposes means the place where a person has his or her permanent home.Domicile is where a person has a legal residence and where they plan to return. One can have homes in multiple places but can have only one domicile. The word "residence" means domicile and the word "resident" means domiciliary. b. Two (2) forms of proof of address must accompany your application. Domicile refers to the place you call home permanently. Your domicile is important for legal purposes such as paying taxes, voting, and claiming benefits.