A visa extension letter should include reference to the proper forms required and the length of and reason for the extension requested. The extension letter serves as a cover for the application and not submitted alone.
A person who overstays the length of time on a visa while in the United States may experience immigration difficulties, including the cancellation of his or her passport. However, there are reasons for which someone on a B-1 or B-2 visa. U.S. Citizenship and Immigrant Services, or USCIS, requires form I-539, the Application to Extend/Change Nonimmigrant Status, be completed before the current visa expires. Further, USCIS suggests that the request for extension be filed at least 45 days prior to the end of the current authorized stay.
The I-539 should be accompanied by a letter that includes the applicant's name, copy of the passport or other documents that show official entry date into the U.S., reason for extension, date current visa expires, and length of requested extension. Individuals with B-2 visas, those with the visit for pleasure designation, may want to include proof of financial support for the period requested as well. It is suggested that a bank statement from the applicant or from whomever the applicant is staying with be included to show that he or she will not be working during the extension. Visitors requesting an extension for family members should include similar information for each person.