Sorry---desktop software cannot be used on an iPad. It can only be used on a full PC or Mac. If you cannot upgrade your OS to support 2019 Premier then you could use online TT instead of desktop. Did you purchased the software from TT?
Call customer support.
To call TurboTax customer support
They are available from 5 a.m. to 9 p.m. Pacific time
Why wasn't I informed of the incompatibility of TT2020 with older Mac OS?
If this can't be resolved. I need a refund ASAP.
TurboTax minimum system requirements for Mac - https://ttlc.intuit.com/community/system-requirements/help/minimum-system-requirements-for-turbotax-...
Go to this TurboTax website to request a refund for the software purchased from TurboTax - https://support.turbotax.intuit.com/forms/refund-request.jsp
Use this TurboTax website to check your orders and payments -