The first step is to download and launch Office 365 Backup Tool on your Windows system.
The opening interface of the software is displayed as shown below. Now, enter Office 365 username and password. Then, click on Connect button and finally click the Next button to move ahead.
You will get a complete display of Office 365 database. All the folders with the number of messages contained by them are displayed on the software panel. Then, hit the Next button.
Select All Mails or a particular folder of Office 365 account whose backup you want to store on the local system.
Under Export Options – Choose a file format (PST, EML, EMLX, MSG or MBOX) in which you want to export Office 365 emails.
Choose an output directory where you want to save the backup results using the Browse button. To start the backup process, hit the Process Now button.