Above The Fold is a term that’s generally used to describe the top portion of a website from a user experience perspective: the portion of a page that a user can see prior to scrolling down the website. This content is known to be above the fold, if you can’t see a piece of content without scrolling down the page, this is known as below the fold.
It’s a good idea to have your important content above the fold, therefore as soon as the user lands on your page they will absorb all of the information without having to take any action. Obviously, there are lots of different devices that render the layout of the website differently, therefore you have to take into consideration both desktop and mobile layouts for maximum effectiveness. You need to ask yourself what elements on your website are crucial to getting your prospects to convert, that’s the information that should be displayed above the fold.
Google released an algorithm update on January 10, 2017 that penalises website with excessive ad placement above the fold on mobile devices.