How to File an Affidavit of Support. Fill in the sponsor's full name, date of birth, and contact information.Specify the relationship to the immigrant. Use our I130 affidavit sample and tips to create a strong affidavit for your spouse. Include these key points and avoid common mistakes. Use this form to show they have adequate means of financial support and are not likely to rely on the US government for financial support. In addition, sponsors must complete the affidavit of support below. Each sponsor must complete an affidavit, so please make copies of this form as needed. Use the sample I751 affidavit as an example. Remember that each letter is unique and should contain elements that are personal to your story.