Retirement tax questions

1) You can use TurboTax 2020 to generate Form 8606 or fill out Form 8606 and file it by itself. 

2) This question is not clear. Did you make a contribution to Traditional IRA for 2021, other than the Roth conversion?

When you recharacterized the Roth IRA to Traditional IRA, it was as if you never contributed to the Roth IRA in 2020. The fact that you failed to file Form 8606 does not make the $6,000 after-tax (non-deductible) pre-tax. You can file 2020 Form 8606 by itself without amending your 2020 return because it won't change other information on your return. When you did the conversion from Traditional to Roth, only the  $100 earnings are taxable. The $100 is not considered an excess contribution. 

Assuming you did not contribute non-deductible Traditional IRA for 2021:

 Enter the Conversion from a Traditional IRA to a Roth IRA

 Inside TurboTax, search for 1099-r and select the Jump to link in the search results

1. Answer Yes to Did you get a 1099-R in 2021?, then Continue
   • If you land on Your 1099-R Entries screen, select Add Another 1099-R
2. Select how you want to enter your 1099-R (import or type it in myself) and follow the instructions
3. Answer None of these apply when you reach the screen Do any of these situations apply to you?
4. 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
5. Next, choose Yes, all of this money was converted to a Roth IRA.

On your Form 1040, Line 4a should be $6,000, Line 4b should be $100, which is the taxable earnings.