If you want to export Office 365 emails to PST for backup, one practical solution is using SysInfo Office 365 Backup Tool. After installing the software, you simply log in to your Office 365 account and select the required mailbox data such as emails, contacts, calendars, or tasks. Then choose PST as the saving format and start the backup process. The software also provides useful options like date filters, duplicate email removal. more: https://www.sysinfotools.com/office365-backup.php