If you are looking for a simple way to backup Office 365 emails, then I would recommend SysCurve Office 365 Backup Tool. With the help of this software, you can save Office 365 emails in PST, EML, MSG, and MBOX formats. Using this tool, you can backup Office 365 emails, contacts, tasks, calendars, etc. With its help, you can export contacts in VCF and calendars in ICS format. The software also comes with a free demo version. Using the trial version, you can export the first 20 items per folder.