Complete the Invitation Letter form. An invitation letter for the sake of a B2 visa is not required.No invitations, no sponsorships - in fact no documentation is required. What should the letter say? Online Nonimmigrant Visa Application, Form DS-160 – Learn more about completing the DS-160. Complete the Invitation Letter form. Fill out the form with correct and sincere information about you, your guest, and the entry and departure date. Ensure that the letter contains accurate, complete, and uptodate details. In the letter, you may want to include a copy of your most recent I-20, passport ID page, F-1 student visa or EAD card (if available). I would like to invite you to come visit me in the United States this summer.