Device may not be supported appears on my iPad screen

You can not install the Desktop program on an iPad at all.  You have to use the Online web version or there is a mobile app you can install.  The Mobile App works with the Online version.

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See this TurboTax support FAQ concerning moving tax files to a new computer - https://ttlc.intuit.com/questions/1901474-how-do-i-move-my-tax-data-file-to-another-computer