My IRA was waived for the year 2020. Where should this notation be put on the 1099R?

Yes, RMDs were waived for 2020.You must indicate to TurboTax that none of the distribution was RMD. If you already enter the 1099-R as RMD and changing your answer to the RMD question doesn't work then you have to delete and renter the 1099-R form. 

If you took a RMD and returned it then please follow these steps:

1. Login to your TurboTax Account 
2. Click on the Search box on the top and type “1099-R”
3. Click on “Jump to 1099-R” and enter your 1099-R
4. Continue until "How much was a RMD?" and select "none"
5. Continue "Tell us if you moved the money through a rollover or conversion" and select "I rolled over some or all of it to an IRA or other retirement account within the time limits (normally 60 days)"
6. Continue answering the questions.

You can verify your entry by looking at your Form 1040 line 4:

1. Click on "Tax Tools" in the left menu
2. Click "Tools"
3. Click "View Tax Summary" in the Tool Center window
4. Click on "Preview my 1040" on the left

Did you take the distribution and roll it back?

If not, and you did not receive a 1099-R, then delete the 1099-R that carried over.