Below process can help you convert format.
Exporting Emails from Pegasus:
Open your Pegasus email client.
Locate the option for exporting or backing up emails. This can often be found in the "File" or "Tools" menu.
Choose a location on your computer to save the exported files and follow the on-screen instructions to complete the export process.

Importing into Outlook:
Open Microsoft Outlook on your computer.
Go to the "File" menu.
Select "Open & Export" or "Open."
Choose "Import/Export."
Select "Import from another program or file" and click "Next."
Choose "Outlook Data File (.pst)" and click "Next."
Browse to the location where you saved the exported Pegasus files and select the .pst file.
Choose the desired options for importing and click "Next."
Complete the import process.