This box will can be filled with an id automatically or manually. It’s used to track from where the user that places a booking comes from.
If it’s created automatically it means that you have configured that users that enter the microsite from an external system or web acess the microsite with this id included in the url. So when they create a booking this will be created with the designated referral id included in that url.
You can also insert manually your desired referral id after booking has been created
