I want to switch from desktop to on line. Are the quoted fees annual or one time?

The software price whether desktop or online is for each tax year. There are differences in the features.

So basically it is one time each year and you need to pay each year to use online or to buy the Desktop program.  Why do you want to switch to online?

The Online web version is only good for one account and one return. You only can see the forms after you pay and download the pdf. And you might need to upgrade to a higher version to enter different kinds of income. You can start an Online return here,
https://turbotax.intuit.com/personal-taxes/online

The CD/Download Desktop you buy and install the program, which can do unlimited returns. The returns are only saved on your computer and can not be accessed from anywhere else. And not saved at Turbo Tax. So Be sure to save Frequently and make backups. You get 5 federal efile for free. In Deluxe and above you get 1 state PROGRAM download to prepare unlimited state returns (in that state). Each state return including the first one is $20 early or $25 to efile or you can print and mail the state for free.

Desktop also has many other features and advantages over the Online version. You can do more than 1 return. You can see and enter into the actual forms. It has a What-If worksheet. And you can use a lower version because all the Desktop versions have ALL the same forms. You just get more help in the higher versions. In online you have to upgrade to enter certain kinds of income. Like Premier for investments.

And the Desktop program is always available even after the year ends. Which is good if you ever need to amend your return after online website is closed or get audited and need your tax records.

TO SWITCH TO ONLINE

If you used the Desktop program last year here’s How to transfer into the Online version, expand the blue link if you used the CD/download last year
https://ttlc.intuit.com/community/entering-importing/help/how-do-i-transfer-last-year-s-return-into-turbotax-online/00/25953

If you used the Desktop program before you may notice several differences and not like the online version. It has less features and no Forms Mode. You can only do 1 return. Your return is only saved online so be sure to save both the .tax2020 data file and the pdf file to your computer when you are done. In case you need to amend in the future or if you need a copy to get a loan or something. You might not be able to access your online return when you need a copy.