Form I-864A, Contract Between Sponsor and Household Member, is for use in only a limited type of green card (lawful permanent residence) applications: Specifically, it should be used in family-based cases where the U.S. citizen or lawful permanent resident who is petitioning for a family member to immigrate does not have sufficient income to serve as the sole financial sponsor.
In such a situation, it's possible for a family member who is living in the sponsor's home to combine their income and assets in order to meet the required 125% of Poverty Guidelines level.
In fact, that household member can be the immigrant, if that person happens to be living and working legally in the United States already, and if the job will continue after the immigrant gets a green card. There's no need for the household member who is the main immigrant to sign Form I-864A to contribute income, however, unless dependent children are also included in the immigration application.
And if the immigrant is contributing only assets (whether a household member or coming from abroad) there's no need to fill out Form I-864A either. Instead, the U.S. petitioner would list these assets in Form I-864 Part 7, Questions 6 to 8.
You can get a free download of Form I-864A from the website of U.S. Citizenship and Immigration Services (USCIS).
The person preparing and submitting this form does not need to be a U.S. citizen or lawful permanent resident in order to sign Form I-864A. This person will, however, need to submit evidence of income (such as tax returns and an employer letter), just as the main sponsor does. The household member will also need to provide proof of being a relative of and residing with the sponsor, such as a copy of a birth or marriage certificate.
By signing Form I-864A, both the main sponsor for the immigrant and the sponsor's household member agree that, while the main sponsor will still fill out a Form I-864 and take some financial responsibility for the immigrant(s), the household member will also provide financial support to the immigrant(s) if needed.
Also realize that, under certain circumstances, it is possible for the household member to become solely responsible for the immigrant's support.
These instructions refer to the version of the form issued 03/10/2021.
Part 1: This section asks for basic name and contact information, to be filled in by the household member. "Relationship to sponsor" means the household member's family connection to the petitioner who is bringing in the immigrant(s).
For Question 7, if the person doesn't have a Social Security Number, that could indicate a lack of valid immigration status, in which case the work is unlawful and won't be counted.
For Question 8, there's no need to worry (or enter anything) if the household member doesn't have a USCIS online account number. This would apply only if it was an immigrant who had certain forms of past interactions with USCIS.
Part 2: This part is to be filled in and signed by the main sponsor, who will be filling out the Form I-864 Affidavit of Support. Self-explanatory.
Part 3: This is to be filled in and signed by the household member, detailing where the person is employed and what the annual income is.
Part 4: This is where the household member indicates how much income they reported on taxes (which hopefully matches annual income; if not, filing an amended return with the IRS might be necessary). In addition, the household member can list assets, if needed to bring the overall support level up. See the discussion of listing assets in this article about filling out the main Form I-864.
Part 5: This is for the main sponsor to fill out and sign.
Part 6: This is for the household member to fill out and sign. If the household member is also the immigrant him or herself, that person does not need to sign Form I-864A unless agreeing to support immigrating children as well.
Part 7: If a language interpreter helped the parties fill out this form, that person's name and contact information need to go here, plus the person's signature.
Part 8: If an attorney or other professional prepared this form, that person's name, contact information, and signature need to go here.
Part 9: This is where you can add information that didn't fit in the main part of the form.
Both the sponsor and the household member(s) will need to sign the I-864A. The sponsor will attach Form I-864A to the main Form I-864 as part of the immigrant's green card application.
Exactly when it gets submitted depend on whether the immigrant will be applying through an overseas U.S. consulate (in which case the National Visa Center will send instructions) or is in the U.S. and will be applying to adjust status (in which case you'd submit all the forms and paperwork to USCIS in one package).