By default, CabGrid Pro will generate a reference based on the date and time the booking is made. This is to insure the booking reference is unique, although this is not guaranteed.
In the CabGrid Pro OPTIONS tab (within the WordPress admin), there are two fields that make up a booking reference seed. The first filed expects a short prefix. This can be anything. For example: TAXI
If not required, the prefix can be left blank. Conversely, if only a prefix is required, the seed input can be left blank. In this case, the system generated number will be prefixed with your prefix.
The second field should be a numerical value. This is the value that will incremented for each booking. For example: 9999
Considering the examples above, the next booking requested would be assigned a booking reference of TAXI10000 (since the numerical value it incremented).
The booking reference will be included with email and SMS notifications sent to both customer and administrator. If the CabGrid Booking Management Add-on plugin is installed, this booking reference will be uses there too.
(This option was introduced in CabGrid Pro v5.9.2)