There are multiple ways to turn the Chat function on or off in a Google Meet.
If you do not have this feature, you will need to force an update to Google Chrome:
1. Click on the Chat icon on the top right of the screen:
2. Click on the button "Let everyone send messages" to turn the Chat on and off. You can turn it off and on multiple times during a Google Meet.
1. Click on the 3 dots in the bottom right hand corner, then click on Settings.
2. Click on Host controls and use the button to turn the Chat function on and off.