what is add_action in wordpress platform

add_action

In Wordpress php functions are seperated and those are defined in seperated file called functions.php.
We can define function as same as our php function
But we need an action tag name for our function
This tag name is used to call function in post or pages in wordpress /p>

<?php
function test(){
    echo "<h2>Hellow Function</h2>";
    }
add_action("test",test);
?>