To view and update client notifications settings go to Clients > Notifications
You will see a list of notifications you can turn on / off and customize.
When Editing a message you will have the option of using placeholders that will automatically get replaced with the proper text. The placeholders are in square brackets and you will have a list of the ones you can use when Editing a message.
Once you Save you can click on 'Preview' to preview:
It may make sense for you to customize the text of the notification for different services. Let's say you offer Walks as well as Boarding, you may have a different Check-in message. Click on the Rules button, select the service(s) and enter the message!
You can also customize notifications for specific clients as well as their secondary contacts by going to a client profile and click on Notifications.