Here is a quick glance at the default locations of SPFILE and PFILE in different platforms. For instance, Linux and Windows.
Please note that, for Windows, directory name and filename are case-insensitive.
There’s no typos in the above path. The default location of PFILE on Windows truly depends on ORACLE_BASE. As you can see, they’re somewhat different on path between SPFILE and PFILE on Windows.
It may be different from version to version.
In some situations, DBA use a PFILE with non-conventional path to startup the database. You need more skills to find the location of PFILE.