I didn't do my taxes for the years 2019-2020-2021 what should I do? because I was overseas

[xmasbaby0]

If you are a U.S. citizen you still are required to file a U.S. tax return if you had taxable income.   You have not provided any other details so we cannot provide any specific advice regarding the returns you need to file or the forms you may need to prepare.

However---the current online program is only for 2021 returns.   Only a 2021 return can be e-filed.   Returns for 2019 or 2020 must be filed by mail.

Online preparation and e-filing for 2018 and 2019 and 2020 is permanently closed.

To file a return for a prior tax year

 If you need to prepare a return for 2018, 2019 or 2020 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/0... 

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 UPS or 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.

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.

If you are getting a refund, there is not a penalty for filing past the deadline.  If you owe taxes, the interest/penalties will be calculated by the IRS based on how much you owe and when they receive your return and payment. The IRS will bill you for this; it will not be calculated by TurboTax.

[DoninGA]

You can still file those tax years.

To complete and file a 2019 and 2020 tax return using TurboTax you would need to purchase, download and install on a personal computer one of the 2019 and 2020 desktop editions from this website - https://turbotax.intuit.com/personal-taxes/past-years-products/

A 2019 and 2020 tax return can only be printed and mailed, it cannot be e-filed.

For tax year 2021 you can use either the TurboTax online editions or the TurboTax desktop editions.  A 2021 tax return can be e-filed using TurboTax at any time on or before October 17, 2022.

TurboTax online editions - https://turbotax.intuit.com/personal-taxes/online/

TurboTax desktop editions - https://turbotax.intuit.com/personal-taxes/cd-download/

[NCperson]

@bkane1982 - while there is still plenty of time to complete this, be mindful that the deadline to receive a refund for the 2019 tax year is July 15, 2023.  After that date, you still owe any tax due,but forfeit any refund due (IRS rules)