Hello I have been using turbotax for years on a PC, for 2020 I am using an IPad I am trying to use the Family Sharing function but am unable to . Is there a Turbo Tax setting I have to turn on? I have checked all the Apple setting and everything is ok

You cannot use the CD/download software on an iPad or any other mobile device.   It can only be used on a full PC or Mac.

Can I use Turbo Tax on my apple mini iPad

This Turbo Tax FAQ will provide information on the requirements. Mobile Requirements

You can also refer to this thread for more information.