You can export your financial data to QuickBooks using the Reports Menu, Standard Reports tab, Finances Group.
However, if you have been using QuickBooks prior to your fair, you have accounts already set up in that program. The standard QuickBooks Export in FairEntry includes account information, so you may have to do some editing before you import the information. See Editing a QuickBooks File Before Importing information about how to do that.
Note: QuickBooks Online does not use the same import process as QuickBooks Pro. If you use QuickBooks Online, please see the QuickBooks Help documentation for how you need to edit the export.