Hooks are WordPress function which we can applied to an action OR and filter

Developer to changed default wordpress functionality for plugins and theme files

Example of a hook

Function custom_excerpt( $output ) {
  if ( has_excerpt() && ! is_attachment() ) {
    $output .= wpb_continue_reading_link();
  }
  Return $output;
}
add_filter( 'get_the_excerpt', 'custom_excerpt' );

Above code is help to add continue link to expert

Filter hook is help to modify the current function ex. 'get_the_excerpt'  wordpress function

Here are some Filters Functions

1. has_filter()
2. doing_filter()
3. add_filter()
4. remove_filter()

function custometheme_enqueue_script() {
    wp_enqueue_script( 'my-mine-js', 'mine.js', false );
}
add_action( 'wp_enqueue_scripts', 'custometheme_enqueue_script' );

Above code help to add Custom JS in your theme file.

Action hook allow to execute custom function

Here are some Actions Functions

1. has_action()
2. do_action()
3. add_action()
4. remove_action()

Hopefully this article to be helpful 🙂