When something “affects” you, it influences you. The word is usually used as a verb.
*The unusually hot weather affected people in different ways. *The doctor said that the disease had affected Dilip’s liver.
The word “effect” can be used as a noun and a verb. An “effect” is a change that has been brought about by something else.
*He is studying the effect of TV violence on child behaviour. *The rising fuel prices had an immediate effect on the economy.
When you “effect” something, what you are doing is bringing about changes. Example, ‘’The Prime Minister has effected many changes by introducing the bill”.
The expression “have an effect on” has the same meaning as “affect”. Example, ‘’The drinking has had an effect on his liver’’.