The loop, or WordPress loop or simply loop, is PHP code that displays WordPress posts. The loop is used in WordPress themes to display a list of posts in a web page.
Inside the loop there are some functions that are run by default to display posts. Theme developers can format the output by using template tags to customize how each post inside the loop is displayed. There are several Template tags that work only inside the WordPress loop and can be used to format, arrange, and publish post data. The WordPress loop is arguably one of the most important aspects of the WordPress code and at the core of most queries in one way or another.