You can take help of most useful Mailsbackup Office365 Backup Tool. It easily creates & take backup of Office 365 emails, contacts, calendars, etc.Direct option to Export Office 365 account to PST, EML, MBOX, MSG, EMLX, DOC, PDF, RTF, HTML, XPS, MHT, CSV, ZIP, etc.With FREE Trial of Office 365 Backup Tool, you can take backup of 25 emails from each folder to any saving option.

Step 1:  Download Office 365 Backup Tool and Select Office 365 from the list.

Step 2 : Enter Your Office 365 Login Credentials and Press Login button.

Step 3: Click the backup button after choosing your saving option and any necessary settings.

Check for more details at: https://www.mailsbackup.com/office-365/