To check whether your database startup with the pfile or spfile

Connect to SQLPLUS as system or sysdba

run show parameter pfile command as below. If it returns a value like below then the database is started with spfile.

SQL> show parameter pfile
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
spfile                               string      /u01/product/11.2.0/dbs/spfileRAPIDS.ora
If the output is blank like below, then the database is started with pfile.

SQL> show parameter pfile
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
spfile                               string