Intelligence is the governing Attribute for Alchemy, Conjuration, Enchant, and Security. It determines your base amount of Magicka, with a normal character having one point of Magicka per one point of Intelligence. This total can be multiplied by your Magicka Multiplier.
Both Enchanting and Alchemy are enhanced by higher Intelligence.
The starting values for Intelligence vary by race and gender:
The following classes receive a +10 Bonus to Intelligence: