How do I file taxes for former year

You cannot use TurboTax Online to file for a past year. TurboTax Online is only for the current tax year, which is now 2021. To file for a past year you have to use the CD or download TurboTax software for the year that you need. You can purchase a download at the following link.

Past Years' Products

You might get a better price from a reputable online seller that still has TurboTax in stock for the year that you need.

Tax returns for past years cannot be e-filed. You will have to print your past-year tax return, sign it, and file it by mail.

TurboTax no longer supports years earlier than 2018. It's too late to get a refund for 2018 or earlier. You can file the tax return, but if it shows a refund you will not get the refund. If it shows a payment due, you have to pay it.