where do we input a 1099R for military retirement? It is not a withdrawal, but a payment?

To enter your retirement income, Go to  Federal> Wages and Income>Retirement Plans and Social Security>IRA  401 k) Pension Plan Withdrawals to enter your 1099R.

To enter, edit or delete a form 1099-R -

Click on Federal Taxes (Personal using Home and Business)
Click on Wages and Income (Personal Income using Home and Business)
Click on I'll choose what I work on (if shown)
Scroll down to Retirement Plans and Social Security
On IRA, 401(k), Pension Plan Withdrawals (1099-R), click the start or update button

Or enter 1099-r in the Search box located in the upper right of the program screen. Click on Jump to 1099-R

Online editions -

On the screen Did you get a 1099-R in 2024? Click on Yes

On the screen Let's import your tax info Click on Change how I enter my form
On the screen How do you want to add your 1099‑R? Click on Type it in myself

On the screen Who gave you a 1099-R? select the type of 1099-R you received and Continue

You enter withdrawals and payments the same way.  I assume you are getting  pension payments from the military?  If it asks you if it was the RMD say all of it is the RMD.   If you need to take the RMD it will ask you if it is the RMD.  Say yes.  Anything your pension pays you is considered to be the  RMD.  Traditional pensions automatically fulfill the rules of an RMD. So for the RMD question put in the same amount as box 1.

i.e. a Distribution/Payment/Withdrawal are all terms relating to money that came out of your Retirment account.

.....Yeah, pension payments are $$ you have no control over once you start them up....but, very loosely, the terms Distribution/Payment/Withdrawal, are referring to the same thing...$$ you received from that provider of Retirment funds.