Write your social security number or federal identification number on your check and the type of tax that you are paying. Never send a check or money order without some form of documentation. This could cause a delay in applying your payment to the proper account. Always include your social security and telephone number on any correspondence, so we may research your issue properly and contact you if we have questions. When mailing returns, always keep a copy for your records. Please notify us in writing when you or your business has a change (i.e. address, your business incorporates, you sold your business, you discontinued your business, etc.).