A separate tax return must be filed for each tax year including only the income and expenses for that year. You can go ahead and file your 2019 tax return using the online product.
To file the 2017 and 2018 tax returns, you must buy, download and install on your computer the tax program for each of those tax years. Here is where to buy it: https://turbotax.intuit.com/personal-taxes/past-years-products/
Tax returns for prior years must be printed and mailed. They can't be efiled. You must print and mail them yourself because TurboTax doesn't print and mail them for you. The tax return for each year should be mailed separately.
