Majorly, affect is used as a verb, while the effect is used as a noun, though the effect can also be used as a noun sometimes, and effectively used as a verb, but in rare cases. When something affects another thing, it leaves an effect on it, while something has surely been affected when there is an effect on it. Sometimes also, affect is seen as a misspelling for effect. When affect comes as a noun, it indicates an emotion or feelings, while effect means the consequences or end results of a process or action.
However, when they are used as a verb, affect means to have an influence on something, while effect means to bring about as a result of something. The synonyms of effect include: to change, influence, modify, overcome, transform, take on, act on, alter, disturb, relate, etc. On the other hand, the synonyms of effect include consequence, outcome, outgrowth, reaction, aftermath, conclusion, etc.