Add Tawk.to Chat to WHMCS.
When the customer is logged in, the chat will have the name and email options filled in automatically. Credit to Jefferson DDR Host!
Clone into WHMCS/modules/addons:
git clone https://github.com/msaulohenrique/tawk_to.git WHMCS/modules/addons
Or download the zip and upload contents to WHMCS/modules/addons/
To configure, go to Setup -> Addon Modules -> Tawk.To -> Cofigure.