Why is my line 16, 17 and 18nof Form 8606 blank?

If you made a Roth conversion in 2021 then please follow these steps to enter it:

1. Click on "Search" on the top right and type “1099-R”  
2. Click on “Jump to 1099-R”
3. Click "Continue" and enter the information from your 1099-R
4. Answer questions until you get to “Tell us if you moved the money through a rollover or conversion” and choose “I converted some or all of it to a Roth IRA”
5. On the "Review your 1099-R info" screen click "continue"
6. Answer "yes" to "Any nondeductible Contributions to your IRA?" if you had any nondeductible contributions in prior years.
7. Answer the questions about the basis from line 14 of your 2020 Form 8606 and the value of all traditional, SEP, and SIMPLE IRAs

If you made any nondeductible contribution for 2021 then please follow these steps:

1. Click on "Search" on the top right and type “IRA contributions” 
2. Click on “Jump to IRA contributions"
3. Select “traditional IRA”
4. Answer “No” to “Is This a Repayment of a Retirement Distribution?”
5. Enter the amount you contributed
6. Answer “No” to the recharacterized question on the “Did You Change Your Mind?” screen
7. Answer the next questions until you get to “Any Nondeductible Contributions to Your IRA?” and select “Yes” if you had a nondeductible contribution before this tax year.
8. Enter your basis in the Traditional IRA from your 2020 Form 8606 line 14 (if you had a basis in the prior year)
9. On the “Choose Not to Deduct IRA Contributions” screen choose “Yes, make part of my IRA contribution nondeductible” and enter the amount (if you have a retirement plan at work and are over the income limit it will be nondeductible automatically and you only get a warning and then a screen saying $0 is deductible).