There are a couple of ways to do this, if you are on our Extra (Growth) plan, your client can log into the customer portal and the customer mobile app and both give the client all of their past and future appointment dates, which pets are booked in and for which services.
All plans also include the option to email out future appointments by searching for the client, and where their appointments are listed on their profile, top right there are 3 little dots. Clicking that will allow you to send out an email with all their future appointments listed.