privelege level in cisco router(0-15).

hai :

hw to configure different prevelge level in cisco router . can any explain detail . privelege level 0 -15 level. and also how to configure username and password for cisco router

Have a look here:
Cisco Privilege Level Article

You can see it as privilege level 15 = administrator.
All below is restricted.

Besides those levels you can also create views where you can decide which commands are available for that view.