The Control file is a file with a .ctl extension that is physically stored on the operating system that is a must for an Oracle database. This file also acts as the brain for our Oracle database. When the Oracle database starts, it reads the parameter file called SPFILE or PFILE and learn the location of the Control file.
the Control file is the brain of our database, the database needs to find this file to work. Because Controlfile includes SCN (System Change number), Datafile paths, Archivelog paths, Onlinelog paths, Backup files and etc.