The greeting property of your bot's Messenger profile allows you to specify the greeting message people will see on the welcome screen of your bot. The welcome screen is displayed for people interacting with your bot for the first time.
Go to "Application Settings"
Click "Facebook Messenger Setup"
Add a "Greeting Text"
Click the button "Save Changes"
Go back to "Application Settings"
Click "Artisan Commands"
Click the button "Execute" for "Add a Facebook Greeting Text to your message start screen."
You can personalize the greeting text using the person's name. You can use the following template strings: