Do you have the tax file ending in .tax2019? Then you need the 2019 Desktop program installed to open it. If you have the Desktop program you should have the License Code. How did you get the Desktop program? Why don't you have the License Code?
If you lost the Code Contact Customer Service 5am-9pm Pacific M-F
https://support.turbotax.intuit.com/contact/
Where is the License Code? Main FAQ
https://ttlc.intuit.com/community/tax-topics/help/i-can-t-find-my-license-code/01/852973
