You can NOT download and install any year on an iPad. You can only install Turbo Tax on a full Windows or full Mac computer.
Here are the system requirements to install Turbo Tax for Windows…..
https://ttlc.intuit.com/questions/1901571-turbotax-for-windows-system-requirements
Here are the system requirements to install Turbo Tax for MAC…..
https://ttlc.intuit.com/questions/1899173-turbotax-for-mac-minimum-system-requirements
