There are several circumstances in Warhammer that call upon you to inflict hits upon an enemy – spells being an obvious example (the Fireball spell causes D6 Strength 4 hits on an enemy unit), as well as things like the Impact Hits made by a charging chariot (covered in the Special Rules chapter). Such hits are resolved using steps 4, 5 and 6 of the rules for shooting attacks.
The only exceptions are hits caused by close combat attacks – these are discussed in the Close Combat chapter.