You can set any custom message while installing messenger, but you can change it anytime in the future by following these steps.
This welcome message is visible to your website visitors when they open the chat widget installed on your website.
Now to set your welcome message, you can follow these 3 easy steps.
Open Messenger settings
Step 1: Click on the Messenger settings button present on the bottom left corner of your messenger inbox.
Customize the welcome message
Step 2: Here the Welcome Message tab is opened by default, You can put any greeting text you like in the field shown below for example 'Hello there!' and a welcome message to introduce your team also the same will be reflected in the live preview of the widget on the left side.
Step 3: Once you are done, hit the Update button to save your changes.