You can't include 2018 and 2019 information on the same tax return. The information for each year must be filed on a tax return for that specific year. If the return you prepared was accepted by the IRS, you will now have to prepare, print, sign and mail an amended return form 1040X for your 2019 information. DO NOT change the return you filed until you start the amended return. Here is a link to help you: https://ttlc.intuit.com/questions/1894381-how-to-amend-change-or-correct-a-return-you-already-filed
Amended returns must be printed and mailed. You must do that yourself because TurboTax does not print and mail it for you. In normal times, it takes the IRS about 16 weeks to process an amended return.
For 2018, you will have to buy, download and install on your computer the 2018 program in order to use TurboTax. Here is a link to buy it: https://turbotax.intuit.com/personal-taxes/past-years-products/
A 2018 return can no longer be efiled. It must be printed and mailed and you must do that yourself. Follow the filing instructions printed with your return for what to include and where to mail it.
