I got interest from Federal Govt for delay in sending return; where do I add this?

Your tax return is the form you send to the government that shows your income and calculates your tax. The money the government sends back to you is your refund. The interest that you received was for the government's delay in sending your refund, not for your delay in sending your return.

Enter the interest the same as interest from a bank account. Enter it as if you got a 1099-INT, even if you didn't. For the payer's name enter Internal Revenue Service, and enter the amount. To enter the interest, type "interest" (without the quotes) in the Search box, then click the link that says "Jump to interest."

@rjs provides a good description of the interest received.  This is how to post it manually.

To manually post a 1099-INT

1. Select Federal
2. Wages & Income 
3. Scroll to Investments & Savings and 
4. select Show More,
5. Start or Revisit next to Interest on 1099-INT - Okay! 
6. Time to kick off your investments! 
7. Yes, on the screen Did you receive any interest income? then Continue.
   • If you see the screen Your investments & savings or Here's your 1099-INT info, select. 
   • Add investments or add another 1099-INT, then Continue.
8. Choose how you'd like to enter your 1099-DIV:
   • If you'd rather manually enter your form, select. 
     • Change how I enter my form, select. 
     • 1099-INT, then 
     • Type it in myself on the following screen.
9. Follow the on-screen instructions to enter the info from your 1099-INT.
10. When you reach the screen Here's your 1099-DIV info, the form you just entered should be listed.

• If you need to enter another 1099-INT, select Add another 1099-INT and follow Steps 4-6 above.

@thcarnwath 

for the interest received in 2022 you use for the 1099-INT.  payee is actually the US Treasury the amount is taxable for state purposes.