Transfer the .pst file from your Windows computer to your Mac.
There are a couple of ways to do this.
ChooseFile > Import, selectOutlook Data File (.pst or .olm) in the first Import window, click the Next button, select Outlook for Windows Data File (.pst), click Next again, navigate to the .pst file you’ve copied to your Mac, select it, and click Import. Drag the folder that contains these messages to the desktop and it will be turned into an mbox file that you can import into Mail.
Follow these steps to open your .PST file in Apple Mail
Go to File menu in On the Outlook for Mac then click Import.
Click Outlook Data File, and then click the right arrow.
Select a data file type, and then click the right arrow.
Locate the data file on your computer, and then click Import.
When the import process is complete, click Done.