how to find database is running with pfile or spfile?

SQL> select decode(value,null,'PFILE','SPFILE') "init file type" from sys.v_$parameter where name='spfile';

init f
------
PFILE

or

SQL> show parameter spfile;

NAME                                 TYPE        VALUE

------------------------------------ ----------- ------------------------------

spfile                               string

if it doesnt returns any value it means the database is started with pfile.