I did this last month. For an important work i need my QuickBooks data on Desktop. For that I simply followed below steps.
1. Choose Company > Export Data:
Step 2: Click to install the ActiveX control. If the Install button is grayed-out, skip ahead.
Step 3: Confirm ActiveX installation:
Step 4: Click Continue:
Step 5: Start the export interview:
Step 6: Select data to import:
Step 7: Select your version of QuickBooks desktop edition:
Step 8: Read and approve special conditions. Important: This step tells you how your data will be changed after the export!
Step 9: Enter contact information:
Step 10: Complete export request:
For images and more information - qbservices.net/export-data-from-quickbooks-online-to-desktop