Which program opens 2020 tax data file. I use a dell computer?

You may need to be more specific, because I read this as what program opens your Turbotax data file and that would be Turbotax, so you may get more help by clearing that up.  If I reading it wrong sorry.....

If you have the tax data file ending in .tax2020 you need the 2020 program installed to open. it.  Did you buy the Turbo Tax Desktop program?  If you paid for the Online version they may give you the Desktop program download.   You need a full Windows 8.1 or higher computer to install it on.  What Windows version do you have?

Here are the system requirements to install Turbo Tax for Windows…..
https://ttlc.intuit.com/community/system-requirements/help/minimum-system-requirements-for-turbotax-windows-software/00/26175

You can buy the program here,
https://turbotax.intuit.com/personal-taxes/cd-download

Contact Customer Service
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7 days a week
https://support.turbotax.intuit.com/contact/

What is the Turbo Tax phone number
https://ttlc.intuit.com/community/using-turbotax/help/what-is-the-turbotax-phone-number/00/25632