Thanks for joining the Community forum, Jillian. I see you want to migrate your QuickBooks Desktop data to QuickBooks Online with Field Service Management.
I recommend contacting the Corrigo Technical Support. They are the best person to help you migrate your QBDT data to QBO. You can visit this article for their contact details, located at the bottom part of the page: Intuit Field Service Management setup and support.
Keep me posted in the comment section down below if you have any other QuickBooks-related concerns. I'll always be around, ready to help. Have a nice day ahead!