I am not provided the Amend button for my 2021 tax return. Any idea why?

[Critter-3]

Have you successfully efiled the original return yet ?  Or did you mail it in ? 

How to Amend ...  https://ttlc.intuit.com/community/amending/help/how-to-amend-change-or-correct-a-return-you-already-...

[DoninGA]

As stated - has the tax return even been filed?

If filed using the TurboTax online editions you would have the option to amend on the TurboTax online Tax Home web page -