You can find the CP or LTR number on the right corner of the letter. Learn how to write a letter to the IRS with our comprehensive guide and sample.Includes ChatGPT prompt. Harris County Tax Office Forms ; Vehicle Registration Forms. MV-506. Pdf, Emissions - testing regulations ; Property Tax Forms. TaxCertRequest. This is the letter I am drafting to the IRS and I will have to paper file. I am not sure who should sign the letter, myself or the taxpayer. See What is backup withholding, later. How to fill out the Harris County Tax Office Authorization Form? These are electronic federal tax forms, equivalent to a paper 1040 and are designed for taxpayers who are comfortable filling out IRS tax forms.