Infinite Scroll is a term used to describe functionality that allows more posts to be loaded on the same page without a new page permalink being created. Visitors scroll down your page and either posts automatically load, or they initiate loading more with a click.

Infinite Scroll functionality may be activated in themes that support it by using the official Jetpack plugin for WordPress. For themes without this support, you must create a child theme, then implement Infinite Scroll yourself following the Infinite Scroll guide on the JetPack website.

Click this link for detailed instructions.