What experience do you have using team-based messaging applications?
There are many options for communication software and messaging applications. Give the interviewer a brief overview of the applications you are experienced in and assure them that you can learn their internal system, should it be new to you.
"I have used a variety of team-based messaging applications - they are powerful tools for encouraging and organizing team communication. I am most familiar with Slack, Apple Messenger and Google Hangouts Chat. Most of these programs are fairly user-friendly and intuitive, so I feel confident that no matter which system you use, I can pick it up very quickly."