Most employers must file quarterly employer returns (Form 941) to report withholding and FICA taxes. However, very small employers ($1,000 or less in employment taxes for the year) can file an annual return (Form 944). If the IRS hasn’t already told you to file annually, you can request annual filing. Do this by mailing your own written request to the IRS (mail to IRS, Ogden, UT 84201-0038) or by calling 800-829-4933 the IRS by April 1.