Affect is a verb meaning to have an influence on.
Example: How do you think the changes will affect you?
Effect is a noun meaning cause or consequence.
Example: What effect do you think the changes will have on you?
Its plural (effects) means movable belongings or goods.
Customs officer: What do you have in this bag?
Traveler: Only personal effects.
Effect can also be used as a verb, in which case it means putting into practice. However, this is quite formal language and it is generally not used in this sense.
Example: What results do you expect after the changes have been effected?