An affidavit of domicile is a short legal document that helps to establish a person's place of residence following his or her death. How do we sign an affidavit of domicile if we are the beneficiaries, coexecutors, and successor trustees of mother's estate?Instructions for Completing Affidavit of Domicile. It will probably be necessary to give the date and time of the decedent's death (according to the death certificate) to further establish proof of residency. Once completed, note the SST number and come into our office to finish the process. Use our Affidavit of Domicile form to verify the last home address of a deceased person to speed up the inheritance process. This affidavit is made for the purpose of securing the transfer or delivery of property owned at the time of the decedent's death to a purchaser.