After you file

The IRS shows they already sent it to you.

 

Double check your bank statements and Check your IRS account (both accounts if married)

Your Online Account | Internal Revenue Service

 

If the IRS thinks they sent it to you but you didn't get it request a trace for a missing third Stimulus payment

https://www.irs.gov/newsroom/questions-and-answers-about-the-third-economic-impact-payment-topic-j-p...

 

Did you get IRS letter 6475?  That is telling you how much they sent you.  If you are married you each get letter 6475 for half.