Do I have to make up a form 1099R and then fill it in somehow to show the amount I SHOULD have taken as RMD? Will that trigger the form 5329? Do I need to enter/create the 1099R at all? Using Desktop version.
If you haven't taken the RMD then take it as soon as possible.
You can request a waiver of the penalty if you have reasonable cause. Please see Relief for Reasonable Cause for additional information.
If you do not have a Form 1099-R from an inherited IRA or are 73 to trigger the RMD questions then you will have to use "forms" mode to file Form 5329 which is only available with the TurboTax Desktop software: