Hi, how can I find out whether I received the stimulus check from 2021?

The third stimulus check was $1400 per person for 2021.  Check your bank account for deposits of $1400 per person during March to May of 2021; check your online account with the IRS to see if the IRS shows they sent you the $1400 per person.

Try checking your online account with the IRS (and if you filed a joint return—check for BOTH of you)

https://www.irs.gov/payments/your-online-account

You can check the IRS website to see the status of the three stimulus payments at this link via your online IRS account. 

Or, if you filed a 2021 federal return, you might have claimed it there and received it as payment against tax liability or as part of your refund. 
This would appear on Line 30 Recovery rebate credit of your Form 1040. 

Click here for a TurboTax Help article with instructions to view your prior year return.