How can i file for 2018 n 2017?

The current online product can only be used to file a 2019 tax return. To file a prior year return, you need to buy and download the TurboTax program specific for the year you want to file and install it on your computer. If you need to file both a 2017 and 2018 tax return, you must buy both the 2017 and 2018 programs. Here is a link to buy them: https://turbotax.intuit.com/personal-taxes/past-years-products/

Prior year returns can't be efiled. You must print and mail them yourself. TurboTax does not print and mail them for you. Use the filing instructions to know what to include and where to mail your return. Mail each year in a separate mailer.