The following applies to direct damage spells:
The target must be an enemy unit.
The target must lie within the Wizard's forward arc (unless specified).
The Wizard does not need line of sight to their target.
The target must be within the spell's range.
Wizards cannot target spells at units engaged in close combat.
Sometimes a direct damage spell will use a template to determine which models are hit. When this happens, the template cannot be placed in such a way that it touches friendly units or enemy units that are in close combat – this is not to say that the template won't scatter onto friends later, depending on the spell. Ranged direct damage spells that use a template have to target an enemy unit by placing the template over the target enemy unit. When targeting a unit with a small or large round template, the hole in the centre must be placed over an enemy model, but only the hole of the template must be within range.