If you have a PST File and you are trying to open it in your system without installing Outlook, then I recommend you use
MSOutlookHelp PST File Viewer, this is the most effective PST File Viewer in Windows systems. The tool consists of multiple features Shows Complete Mailbox Data through which you can see complete PST data, including emails, contacts, calendars, tasks, journals, attachments, and other items. Additionally, you can also
search specific emails in Outlook with the help of this software.