If you are asking to pay for online TurboTax using the license key for the desktop download--no, you cannot do that. If you do not own or have access to a full PC or Mac on which you can use the download then seek a refund for the download and pay the fees to use online TurboTax.
To request a refund for a TT product
https://ttlc.intuit.com/turbotax-support/en-us/help-article/intuit-refunds/request-refund-turbotax-p...
ONLINE 2024
https://turbotax.intuit.com/personal-taxes/online/
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**