The autocomplete function allows you to select an existing customer profile in the Customers section of your dashboard when creating a booking or selling a gift voucher from your Calendar.
When you start typing  the first or last name of a customer in the Customer tab of a booking or gift voucher, a list of customer profiles matching your entry appears . The list is filtered as you continue typing.
If you select a customer profile from the list, the system will automatically populate the Customer tab with the customer details for that customer profile, and the booking or gift voucher will be linked to that customer profile.
If you do not select a customer profile from the list, and fill the Customer tab with the same details as an existing customer profile, you will create a new customer profile. If needed, you can merge the duplicate customer profile by following these steps here