Yes, under the Clients Tab, you can send an announcement to all current clients or prospects in a kitchen. The messages will be sent through The Food Corridor and appear as messages in your clients' accounts. If your client opted to receive notifications by text message or email, they will receive a notification that they have a message.
To message all clients if you're on a computer:
Check the box to the left of Business Name in the Clients tab
Do this for each page of clients
Click Message at the upper right side of the screen
You can do the same for prospects. See below:
On mobile, simply click "All Options" on the Clients tab then "Message Active Clients" or "Message In Progress Prospects".