I have not received my 1099R for my RMD. where do I post it on turbo tax

You HAVE to get a copy from the plan.  Maybe you can find it on their website.  Call them.

The only way to enter a RMD in TurboTax is when you enter the related 1099-R. There's no other way to report your RMD.

Since you had a distribution, it is required that the firm issue you a 1099-R.  As mentioned in the comments, you might be able to log into an online account and access your "tax forms" or contact them directly about the form.