If you want to generate a report which shows repeat customers, or the number of bookings made by each customer:
1. Go to Marketing>Reports.
2. Click on Customers.
3. Click on the Go button to generate a report.
4. Click on the Download as xls button to download the report
5. In the report, you will see the total number of bookings made by your customers. If the number is higher than 1, the customer is a repeat customer.