Each applicant must demonstrate the intent to reside indefinitely within the State of California and in the County of Santa Clara. This article discusses the difference between domicile and residence in this context, and how sponsors can establish and prove their domicile for Form I-864.Providing proof of domicile in the United States is critical for most people when submitting Form I864, Affidavit of Support. "The released documents are to be used only in the above captioned Santa Clara County Superior Case. A minimum of three documents will be required. Category A - One (1) Required, Category B - Two (2) Required, Category C - Three (3) Required. How do I handle a proof of domicile when filling Form I864? To complete Form I-864, the petitioner must meet certain requirements.