If you mailed in your extension form, the IRS knows you requested an extension. There is nothing special to mark on your tax form. Just prepare your return normally. Make sure you have entered any payment you made when you sent in the extension form.
When you requested your extension you were supposed to pay your estimated tax due. Did you enter the payment you made into your tax return? Go to Federal>Deductions and Credits>Estimates and Other Taxes Paid>Other Income Taxes
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
