RE: how to transfer data files from outlook into outlook web appl with 365

Hi Christian,

It is required to set up in Outlook client. You can add an Office 365 email account to your current Outlook profile and export non-office 365 account email to PST,. After that, import PST to Office 365 account.
1. Export Outlook items to an Outlook Data File (.pst)
2. Connect Outlook to Office 365 account
3. Import Outlook items from an Outlook Data File (.pst)

Thanks,
Johnny Zhang