To claim a refund, you must file an amended return within 3 years after the date you filed your original return or 2 years after the date you paid the tax. Many find the easiest way to figure the entries for Form.X is to first make the changes in the margin of the return they are amending. Once completed, use these instructions to submit your application. ​. INDIVIDUAL ACT-32 Forms. You should file an amended IT 1040 or SD 100 any time you need to report changes to your originally filed return(s). The following is a list of interactive forms. These forms should be downloaded and completed on your device and printed. Wondering where to pick up your tax forms this year, or how to get assistance preparing and filing your taxes? Letter evidencing tax exemption under Section 501(c)(3) of the IRS code.