Underneath the File menu is a rightward pointing arrow ( >). The default view is often something similar to this: The easiest and quickest way that I know of is to open the “tree view” of your folders, if you haven’t already. I’m using Outlook 2013, but the technique is similar for older versions. Rather than telling you where the default location is, let’s use Outlook itself to tell you the exact path of your PST file and then use Windows itself to do the same. Of course, there’s always a chance that your PST is stored in some other, non-default location. The default location has changed a time or two over the years. (Not to be confused with, the online mail service from Microsoft, which is completely unrelated.) PST files are actually fairly complex databases that contain your mail, your calendar, your contacts, and even more when you use Microsoft Office’s Outlook mail program.
PST stands for “ Personal STore” – as in your personal mail storage.