Yes if you download the .tax2021 file you need the Desktop program installed to open it. You should also download the pdf file with all the worksheets.
If you call in they might give you the Desktop program if you paid for the online version.
How to contact Turbo Tax
https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-contact-turbotax/00/26991
What is the Turbo Tax phone number
https://ttlc.intuit.com/community/using-turbotax/help/what-is-the-turbotax-phone-number/00/25632
