"Why does the form that turbotax uses have to be approved"
Because TurboTax is a ERO service provider licensed by the IRS and must comply with all IRS regulations. Any form that TurboTax has must meet the IRS specifications for that form and must be submitted to the IRS for final approval before it can be released.
That is mainly for e-filing since the form encrypted by TurboTax according to IRS specifications must be able to be unencrypted by the IRS when they receive it so it must pass all IRS tests prior to release.
There are only a few "mail only" forms and the IRS does not have a different procedure for those - all forms must go though the same testing. And paper filed forms must also meet IRS specifications so that they can be machine scanned by the IRS when received to avoid manual data entry.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
