im trying to file previous taxes in 2020 -2021 for the stimulus tax check i never recieved

It is too late to file a 2020 return and get the 2020 stimulus money.  The deadline to do that was May 17, 2024.   If no one could claim you as a dependent in 2021, you could still file a 2021 return to seek the recovery rebate credit for the 3rd stimulus.   If someone could claim you as a dependent in 2021, you cannot get the stimulus money.    The credit is in Federal Review and will show up on line 30 of the tax form 1040.

You cannot change the tax year.   The current online program is for 2024 only.   Only a 2024 return can be prepared online and only a 2024 return can be e-filed.

Online preparation and e-filing for 2021, 2022, and  2023 is permanently closed.

Note:  The desktop software you need to prepare the prior year return must be installed/downloaded to a full PC or Mac.  It cannot be used on a mobile device.

To file a return for a prior tax year

 If you need to prepare a return for 2021, 2022, or 2023  you can purchase and download desktop software to do it, then print, sign,  and mail the return(s)

https://turbotax.intuit.com/personal-taxes/past-years-products/

You may also want to explore purchasing the software from various retailers such as Amazon, Costco, Best Buy, Walmart, Sam’s, etc.

Remember to prepare your state return as well—if you live in a state that has a state income tax.

https://ttlc.intuit.com/community/state-taxes/help/how-do-i-contact-my-state-department-of-revenue/00/25573 

When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s.  Use a mailing service that will track it, such as certified mail so you will know the IRS/state received the return.

Federal and state returns must be in separate envelopes and they are mailed to different addresses.  Read the mailing instructions that print with your tax return carefully so you mail them to the right addresses.

Or use the paper forms to prepare by hand to mail in.

Here is the IRS 2021 Form 1040
https://www.irs.gov/pub/irs-prior/f1040--2021.pdf

or if you want bigger type use 1040SR for Seniors,
https://www.irs.gov/pub/irs-prior/f1040s--2021.pdf

And 2021 Instructions
https://www.irs.gov/pub/irs-prior/i1040gi--2021.pdf

2021 Tax and EIC Tables
https://www.irs.gov/pub/irs-prior/i1040tt--2021.pdf

Sch 1 : https://www.irs.gov/pub/irs-prior/f1040s1--2021.pdf
Sch 2 : https://www.irs.gov/pub/irs-prior/f1040s2--2021.pdf
Sch 3 : https://www.irs.gov/pub/irs-prior/f1040s3--2021.pdf

The stimulus payment issued in 2020, EIP1 and EIP2, are no longer available since it is beyond the 3 years from the due date of the tax return.

The stimulus payment for 2021 is available if you were eligible for payment in 2021.  If you were being claimed as a dependent on a 2021 tax return you are not eligible.

If you filed a 2021 return then you will have to amend the return for the Recovery Rebate Credit.  An amended return can only be printed and mailed.  If will take the IRS 16 weeks or longer to process the amended return.

See this TurboTax support FAQ for amending a prior year tax return - https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-already-filed/L4VjJ9BA2_US_en_US?uid=ld1n99kr

If you never filed a 2021 tax return -

To complete and file a 2021 tax return using TurboTax you would need to purchase, download and install on a personal computer one of the 2021 desktop editions from this website - https://turbotax.intuit.com/personal-taxes/past-years-products/

A 2021 tax return can only be printed and mailed, it cannot be e-filed using TurboTax.

Before you file anything make sure that the IRS has not already sent the stimulus payment of $1,400 to you back in 2021.  Go to this IRS website and open your Tax Account - https://www.irs.gov/payments/online-account-for-individuals

trying to fill out a stimulus

app 

I need file for 3 stimulus check