WordPress Hooks
A WordPress page is assembled by tons of functions and database queries. The WordPress Core, plugins, and theme work together to output the page elements like text, images, scripts, and styles. Once fully assembled, the browser then puts them all together and renders the page.
WordPress hooks allow you to ‘hook into’ this build process at certain points and run your custom code. The main function of hooks is to allow you to modify or add features to WordPress without touching the core files.