'The fold' is a term that was used to indicate that the most important content should be placed in the top of the page, the part you can see without scrolling. The reasoning behind this was that people didn't scroll down, and everything below the fold would be missed. As a result of this people crammed all the content above this line, regardless of whether this was appropriate. This results in a cluttered, user-unfriendly website
In the last few years studies have shown that people do scroll past the fold, so it has become something of the past.
You can place important elements in the natural flow of the page.