How to add an email client to wordpress for my orgazniation

Hello, I am currently building this site https://www.bilsan-south.com i made a few custom emails for everyone in my office, i set up the emails with their gmail accounts so they can send and recieve emails without having to log into the hosting account..Now i want them to be able to use their email from the company website. i want to have an email section on the website where they can log in and read and send emails from. Is there some kind of a plugin for an email client where i can do that? can be free or paid.