It's possible to add more text to the email notifications sent from when you book a meeting, in case you want bookers to get some additional information.
You need to be administrator in your solution to set this up.
Go to settings
Scroll down to Custom email text for meeting creation
Just start typing your extra text. Don't forget to press save!
Please note, this text cannot handle any type of formatting. A low tech solution is to copy the text into a notepad and then copy it from the notepad into this Planner window.