Each spell has a casting time and a level. (93, 100-103)
To cast a spell, the caster must have it firmly fixed in mind, or must have access to it in a magic item.
With the exceptions of cantrips and rituals, a caster can cast only a limited number of spells before resting. See spell slots.
The target of a spell must be within the spell’s range. See also area of effect.
A spell’s components are the physical requirements you must meet in order to cast the spell.
Each spell has a duration. Some spells require concentration.
Dice Rolls. Some spells specify that a target can make a saving throw to avoid some or all of a spell’s effects. Some require the caster to make an attack roll.