Import PST file to Office 365 With User Admin Account
After clicking on Add files button you are navigated where you need to select PST files from the browse window and click on the "Open" button.
You can even add the the entire folder as stated above.
Click on the Add folder button to import Outlook PST to Office 365.
Navigate and select folder containing PST files and click on the "OK" button.
All the PST file will be listed and provide the the email addresses corresponding to the PST file names, Also the credentials will be validated at the same time as shown below:
A CSV file can also be added to the Office 365 Import software by using the "Add CSV" button, You can click on the Sample CSV button in order to view the CSV file format. The format is like this.
Press the "Import" Button and start the process to import PST file to Office 365 mailbox account.