i am missing my tax return 2021

  You have to access your own account and/or  print it for yourself using exactly the same account and user ID that you used when you prepared the return.

 https://myturbotax.intuit.com/

Start a 2024 return online and enter some personal information  so that the menu on the left opens up and lets you access your past year returns.

https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-access-my-prior-year-return/01/27010

https://ttlc.intuit.com/turbotax-support/en-us/help-article/import-export-data-files/save-2021-turbotax-online-return-pdf/L8dHfRkpT_US_en_US?uid=m5y4ch1y

Many people have multiple TT accounts and forget how to access them.  Log out of the account you are in now.

https://ttlc.intuit.com/turbotax-support/en-us/help-article/account-management/many-intuit-accounts-turbotax/L9aVfKS1Z_US_en_US?uid=ll5g6zcx

Account Recovery

Or did you use the desktop version of TurboTax?  If so, the files are on your own hard drive or any backup device you used like a flash drive.

https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/find-last-year-tax-data-file-tax-file-computer/L0XJvPaJr_US_en_US?uid=m6gufxei

https://ttlc.intuit.com/turbotax-support/en-us/help-article/data-systems/find-tax-data-file-mac/L4VNGm33S_US_en_US?uid=m6guhab0

You can get a free transcript from the IRS or for a fee of $30, an actual copy of your tax return.

https://www.irs.gov/individuals/get-transcript

https://www.irs.gov/pub/irs-pdf/f4506.pdf

SAVE YOUR TAX RETURNS !

EVERY year before mid-October you should save a copy of your tax return as a pdf and print a copy of it for your records.  That way you will not be searching online frantically when you need it for a lender, FAFSA forms, your next tax return, etc. 

https://ttlc.intuit.com/turbotax-support/en-us/help-article/import-export-data-files/save-2021-turbotax-online-return-pdf/L8dHfRkpT_US_en_US?uid=m6guj526

https://ttlc.intuit.com/turbotax-support/en-us/help-article/import-export-data-files/save-2021-turbotax-online-return-pdf/L8dHfRkpT_US_en_US?uid=m78eb8pc

In order to transfer a past year return to the new return you need the tax file

https://ttlc.intuit.com/turbotax-support/en-us/help-article/import-export-data-files/save-turbotax-online-return-tax-data-file/L4xwOG3LF_US_en_US?uid=m6guk3xl

NOTE:  TurboTax and the IRS save returns for seven years.  Returns older than seven years are purged.