If you need to import multiple PST files to Office 365, you have two ways like Manual or automated methods. Microsoft provides methods such as Network Upload and Drive Shipping through the Microsoft Purview portal, but these require multiple configuration steps and can be time-consuming, especially if have have many PST files.

For a quicker and secure approach, you can use a dedicated migration tool like MailsDaddy PST to Office 365 Migration Tool. It allows you to add multiple PST files at once and import them directly into Office 365 mailboxes. The tool preserves the original folder structure, email formatting, attachments, contacts, calendars, and other mailbox items throughout the migration. It also supports bulk migration, mailbox mapping, and selective data transfer with easy to use interface. It is an ideal choice for both individuals and organizations managing large-scale PST imports.