You are able to file your 2018 return with TurboTax. Click the following link to select which 2018 version would best fit your needs: https://turbotax.intuit.com/personal-taxes/past-years-products/
You should file 2018 first, then work on 2019. There might be information from your 2018 return that needs to be entered on your 2019 return.
Click here to chose which version of 2019 would be fits your needs: https://turbotax.intuit.com/personal-taxes/online/
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