As it's a noun, the only other possible version is the plural 'effects.' 'Effect' is usually preceded by an article (i.e., 'a,' 'an,' or 'the'). Notice that 'effect' is written with 'an' in front. (This means 'I want to create a result the world will remember.')

I want to create an effect the world will remember.

Put simply, 'an effect' means 'a result.'

You must be pleased with the effect you've created.

Your lectures had an immediate positive effect.

It can also mean result, outcome, consequence, or appearance. In basic terms, 'effect' means a result, but that is also too simplistic. As it's a verb, the following versions are also possible: 'affects,' 'affecting,' 'affected,' and 'affect' (without 'to' in front). In this example, notice that 'affect' is written with 'to' in front. (This means 'I want to change the vote.') Put simply, 'to affect something' means 'to change something.' (Mark's experiences in Africa transformed his outlook on life.)

Mark's experiences in Africa affected his outlook on life.

It can also mean to have an impact on, or to transform. In basic terms, 'affect' means to change, but that is too simplistic.

It does not affect me