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.Comprehensive guide to writing an invitation letter for your US visa application, with free samples and tips. There is no requirement for an invitation letter. If you want to send on send it to your parents who in turn may present it to the US consulate. The letter should include specific details like your relationship with the visitor, the purpose of their visit, duration of stay, and financial arrangements. What should the letter say? This template is readily available for download in MS Word, Google Docs, and Apple Pages formats, ensuring compatibility with various word processing software.