"I did not receive any documents for tax year 2022 to document that conversion."
That's because you had no 2022 conversion. Conversions occur in a particular year, not for a particular year.
Contributions and conversions are separate transactions. The $6,000 nondeductible traditional IRA contribution was reportable on a 2022 Form 8606, resulting in $6,000 on line 14 of that form that carries forward to line 2 of your 2023 Form 8606. That gets added to the $6,500 contribution on line 1 of the 2023 Form 8606 to give you a total on line 3 of $12,500 to be used in calculating the taxable amount of your 2023 Roth conversion(s).
Apparently you failed to report the nondeductible traditional IRA contribution made for 2022, so you need to amend your 2022 tax return to include the required Form 8606 and send that along with Form 1040-X where you'll provide your explanation for filing the form now.
