The 3rd Stimulus payment was 1,400 per person. It was sent out based on your 2020 return. If you didn't get the full amount or qualify for more (like you added a new dependent) you will get the extra on 1040 line 30.
If you are married you may each get a letter showing half of what you got. You need to double check the amount with your bank statements. If you didn't get the spouse letter you should check each account at the IRS. Check each IRS account
Your Online Account | Internal Revenue Service
