I've never filed taxes before, and put my income from 2017, 2018, 2019, and 2020 all on my 2020 return. What should I do to fix this? Thank you.

Did you already file the 2020 tax return with the income from earlier years included? If not, go back through the return in TurboTax and delete all the income from the earlier years. If you already filed it, you have to file an amended return (Form 1040-X) for 2020 to remove all the income from the earlier years and leave just your 2020 income.

In either case, you also have to file tax returns for 2017, 2018, and 2019 - a separate return for each year. It's too late to get a refund for 2017. If your 2017 tax return would show a refund, you might as well not file it, although you might want to file it just to make sure the IRS doesn't bother you about it. But if it shows a payment due, you have to pay the amount that is due.

See the following FAQ for instructions to amend your 2020 tax return.

How do I amend my 2020 return?

It normally takes the IRS 16 weeks to process an amended return, but they are severely backlogged this year, so expect it to take much longer than that.

Don't file the amended return until your first return has been accepted and you have received the original refund. This is especially important if you included W-2s from earlier years, because the IRS might make changes to the return that you filed, and you might not get the refund that you are expecting.

You cannot use TurboTax Online to file for past years. TurboTax Online is only for the current tax year, which is now 2020. To file for the earlier years you have to use the CD or download TurboTax software for each year that you need. You can purchase downloads at the following link. You have to purchase a separate program for each year.

Past Years' Products

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

Tax returns for past years cannot be e-filed. You will have to print your past-year tax returns, sign them, and file them by mail. Mail each year in a separate envelope. The IRS backlog will also delay the processing of your past-year tax returns, so this is all going to take a long time to get straightened out.

If you live or work in a state that has income tax, everything that I've said here applies to your state tax returns as well as federal. Federal and state returns have to be mailed to different addresses.