Purpose of Form
In most cases, people who are applying for a nonimmigrant visa to the US have to file a special Form I-864 (Affidavit of Support), which proves that there is a person in the US who can financially support you. It was made in order to avoid situations, which turn this person into a real burden on the US social assistance programs. Moreover, it has to stop these people from taking illegal work. However, there are also exceptions from the general rule of filling Form I-864 (Affidavit of Support).
Some people are not obliged to fill Form I-864 (Affidavit of Support). For example, if you have a passive income outside the US, independent means or other reliable sources of income, you can fill USCIS Form I-864W (Intending Immigrant's Affidavit of Support Exemption). In fact, this form shows that you don’t need a sponsor.
January 7, 2020