What is the most important stat for wizards?
Int: A Wizard's first priority should be to get 20 Intelligence. Their second priority should be to find a way to exceed 20 Intelligence, but there are very few ways to do that. Wis: Good for Wisdom saves. You want a bit to protect yourself, but fortunately wizards are also proficient in Wisdom saves.
What are the best stats for a wizard?
Charisma and Strength can both be dumped stats for a Wizard. They do give you stuff, like carrying capacity and higher social skill bonuses, but other member of your groups may be naturally better at these. After racial stat increase, I'd try to have 16 Int, 14+ Con and Dex, and a minimum of 10 wisdom.