Welcome messages are received by the users when they started interacting with your bot. Users will receive this message once they click the “Get Started” button on your Messenger chatbot.
To enable this feature on your chatbot, follow the steps below:
Step 1: Go to the Menu section (left part of your dashboard)
Step 2: Click Settings on the list of features on the menu
Step 3: From the top navigation Tab click on Channels.
Then click on the Facebook Messenger bot channel
Step 4: There you can edit the welcome message on the column given there.