Although not a requirement, your U.S. host can write a letter. We've provided a sample invitation letter for a B-2 visitor visa.How to Write a Letter of Invitation for a U.S. Visa Application? Remember that your Cuban visitor needs your Invitation Letter before the process begins! Comprehensive guide to writing an invitation letter for your US visa application, with free samples and tips. While the US resident can write an invitation letter, the visa officer will never use it to evaluate the applicant's eligibility for a visa. Each individual requesting an invitation letter must fill out a separate form. All letters will be sent in PDF form to the e-mail address provided. The template is designed in both A4 and US letter sizes, accommodating international and domestic visa requirements. The letter is a medium that tells the consular officer that you have someone inviting you to stay with them for a while in the country.