Why do I need to wait on form D400 p1,2?

If you’re referring to the two-page North Carolina Form D-400, 2021 Individual Income Tax Return, it’s not yet available.  The tentative release date is February 17, 2022.

Please see the TurboTax Help article State forms availability table for TurboTax individual (personal) tax products for more information.

All individuals, including part-year residents and nonresidents, who are required to file a North Carolina individual income tax return need to file Form D-400.

If you're referring to a different form, please clarify.

[Edited 1/26/2021 | 6:03 am PST]

Because

For either paper-mail filing, or e-filing, NC isn't accepting any files until the middle of February,  "currently" scheduled for 17 February....but that could change:

North Carolina Individual Forms Availability (intuit.com)

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The reason for the lateness, is that NC DOR won't be ready to take any forms until then....and doesn't really want anyone to try filing until they are ready.