How do I upload my t4s from CRA to file my 2016 ,2017,2018 taxes

Here is how to use CRA Auto-Fill:

1. In the upper-right area of TurboTax, select Find.
   Note: If you don’t see the Find button, you may not have completed the "Setting up" section of your return. Continue through the Setting up section until the Find button appears.
2. In the Find window, type “Auto-Fill.”
3. From the list of search results, select Auto-Fill My Return, then select Go.
4. On the Name, get a jump start on your tax return step, select Continue.
5. On the Let’s import your info step, select Launch CRA site.
6. Follow the steps to download your slips and other information.