I will install and configure zimbra mail server

Zimbra Collaboration Server is open-source collaborative software that comprises a mail server and a web client. It allows for email, calendaring, creating users and distribution lists, file sharing, chatting, managing mail server activities

Zimbra is a cost effective and best alternative of G-Suite and Office 365 with unlimited domains

And emails and it is the best solution for your business owners.

Zimbra has Email, Calendar, Documents, Chat and lot of other features. You can use web based email client or configure on any Mobile / Desktop client like Outlook, Thunderbird or Apple Mail.