There are five type of files

Parameter files – These files tell the Oracle instance where to find the control files.
For example, how big certain memory structures are, and so on.
The files that make up the database are:
Data files – For the database (these hold your tables, indexes and all other segments).
Redo log files – Our transaction logs.
Control files – Which tell us where these data files are, and other relevant information about
their state.
Temp files – Used for disk-based sorts and temporary storage.
Password files – Used to authenticate users performing administrative activities over the
network.