I filed 2021 using Turbotax online. i need to file an amendment but don't see any option to do this on the website. How do i file an amendment online?

https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-already-filed/L4VjJ9BA2_US_en_US?uid=lcy94np5

Only certain paid tax pros can still e-file past year amended returns. You cannot e-file an amended return that you prepared yourself using TurboTax.  Your 1040X must be printed, signed and dated in ink, and then you need to mail it in.  Use a mailing service like certified mail so you will know the IRS received it, since you will have a long wait for it to be processed.

Even during “normal” times it takes about four months for the IRS to process an amended return.  During the pandemic and due to the severe backlog at the IRS it is taking much longer—six to nine  months or more for many amended returns.  Do not expect quick results from amending.  When the IRS issues a refund for an amended return it will be by check.  They do not make direct deposits for refunds for amended returns.  You can watch for information here:

https://www.irs.gov/Filing/Individuals/Amended-Returns-(Form-1040-X)/Wheres-My-Amended-Return-1