You cannot use the current TurboTax program to file a 2018 tax return. The current program is only for filing a 2019 tax return. To prepare, print, sign and mail a 2018 tax return, you must buy and download the 2018 program and install it on your computer. Here is a link to buy it: https://turbotax.intuit.com/personal-taxes/past-years-products/
If you entered 2018 information in the 2019 program, you must delete it and start over in order to enter your 2019 tax return information. Here is how to clear and start over: https://ttlc.intuit.com/questions/2586254-using-clear-start-over-in-turbotax-online
