If you mean the 3rd stimulus for $1400 there is no place to put anything about that on your 2020 return. That check is issued separately by the IRS and has nothing to do with your 2020 return.
TurboTax cannot track your 3rd stimulus or tell you when it will arrive. The IRS is issuing 3rd stimulus checks on its own timetable.
You can use the IRS Get My Payment site to see what is expected for your 3rd stimulus check:
You can enter the information about receiving either the 1st or 2nd stimulus checks on your 2020 return by using the recover rebate credit.
The stimulus check is an advance on a credit you can receive on your 2020 tax return. If something went wrong or you did not get the stimulus check in 2020, you can get it when you file your 2020 return in early 2021
The Recovery Rebate Credit will be found in the FEDERAL REVIEW section. ( you should see "Let's make sure you got the right stimulus amount”) If you are eligible it will end up on line 30 of your 2020 Form 1040.
Make sure that you enter ALL of the stimulus money received for the 1st and 2nd stimulus for yourself, your spouse and your children.
Click on Tax Tools on the left side of the screen. Click on Tools. Click on View Tax Summary. Click on Preview my 1040 on the left side of the screen.