There are several fax numbers for the Internal Revenue Service depending on whether the matter is business or personal and the geographic location where the taxpayer resides, explains the IRS. The best way to determine the correct number is to visit the IRS website.
The IRS is divided in several departments. For personal tax issues, there are three primary divisions for those residing in the United States and one that handles citizens living abroad, according to the IRS. The correct fax number to use is based on the taxpayer's geographic location. Typically, the office closest to the taxpayer is the correct number to use, but there is a chart on the IRS website that shows a taxpayer which number to use for their state.