You can easily convert MBOX data into OFFICE 365 by using Recoveryfix for MBOX to PST software. It can convert multiple MBOX files to PST, EML, MSG, and Office 365 without data loss. The software performs accurate and secure MBOX data migration from 20 email clients, including Apple Mail, Thunderbird, Zoho Mail, Eudora, WebMail, etc.
Tool link-> https://www.recoveryfix.com/mbox-to-pst-converter/