Form 8606

You have to enter the contributions before you enter the conversion. Delete the conversion part to get the 8606 basis. Then enter the conversion.

The programs and wording of questions vary but this should get you through. From GeorgeM777:

First:   Enter the Non-Deductible Contribution to a Traditional IRA

1. Select Traditional IRA on the Traditional IRA and Roth IRA screen and Continue
2. Answer No to Is This a Repayment of a Retirement Distribution?
3. On the Tell Us How Much You Contributed screen, enter the amount contributed and continue
4. Answer No on the Did You Change Your Mind? screen
5. Answer the questions on the following screens, until you reach Choose Not to Deduct IRA Contributions. Select Yes, make part of my IRA contribution nondeductible and Continue

Step 2:  Enter the Conversion from a Traditional IRA to a Roth IRA

1. Inside TurboTax, search for 1099-r and select the Jump to link in the search results
2. Answer Yes to Did you get a 1099-R in 2021?, then Continue
   • If you land on the Your 1099-R Entries screen, select Add Another 1099-R
3. Select how you want to enter your 1099-R (import or type it in yourself) and follow the instructions
4. Answer None of these apply when you reach the screen Do any of these situations apply to you?
5. Select I converted some or all of it to a Roth IRA on the Tell us if you moved the money through a rollover or conversion screen
6. Next, choose Yes, all of this money was converted to a Roth IRA
7. Continue answering questions until you come to the Your 1099-R Entries screen

To check the results of your backdoor Roth IRA conversion, see your Form 1040:

1. On the left side of your screen, select Tax Tools, then Tools
2. Under Tool Center, select View Tax Summary
3. On the left side of your screen, select Preview my 1040
   • Your backdoor Roth IRA amount should be listed on Form 1040, Line 4a  as IRA distributions
   • Taxable amount should be zero unless you had earnings between the time you contributed to your Traditional IRA and the time your converted it to Roth IRA, then the earnings would be taxable
   • Schedule 1, Line 20 IRA deduction, should be blank
4. Select Back on the left side of your screen to return to where you left off in TurboTax