To send a private event to your customers, you'll have create a new service. Head to Setup > Manage services, and click Add service. Under Online booking settings > Visibility on booking tools make sure to set this service as "Not visible online":
Now you'll have to create the widget so that you're able to get a private URL.
Then follow these steps to create a specific widget for this private service:
Go to Booking tools and select Manage booking widgets
Click Create new widget
Select Embed or Popover mode
Name your new widget (this is for internal reference only)
Filter by service and choose the new service you created
Customise as needed
Don't forget to save the widget
Then click on Get embed code
Embed the widget on your website or circulate the widget URL
This service won't show on your Booking Page or other booking tools and will only be available to people with the link 😊