Yes, Gymcatch has inbuilt messaging across all of our products.
You can select to message attendees from anywhere you have a list of customers presented using the Message button, such as the Attendees pages of your sessions or courses, the list of Package customers for a bundle, pass or membership, or you can select all or a sub-set of customers to message on the Customers page (check the box next to each customer to create a selection or use the checkbox in the top bar to select all the customers > Actions > Message).
Please note that any messages sent to sub-profiles will be sent to the 'parent' account.