Execute a custom function on 'user register' or 'login' I am new to Drupal. I want to execute my custom function every time when user registers or logins to my site. How can I do this?
You can do this using the following hooks in your module.


hook_user_login
hook_user_register (In D7 we had user_insert hook.)


Examples:

User Login Hook:

function mymodule_user_login($account){

   //your code here
}


User Register Hook:

function mymodule_user_insert(Drupal\Core\Entity\EntityInterface $entity){

   //your code here

}