is there any way to add a content locker script to the login of a wordpress website, im offering a free service to my visitors ( mobile unlock code ) which will be sent to their inbox on wordpress, i would like to make money by locking the login form so that they fill a survey and then get access to the content.
Is this possible?

Sure, go into your themes functions.php in the theme editor and add this code:

Code:

function do_the_lock() {
	echo "Content locker code here";
}
 
add_action('login_head', 'do_the_lock');

Just put in your locker code where it says and it should be ready to go. If you get errors it will probably be because the locker code wasn't escaped, so if your locker code has double quotes in it just put a \ in front of each double quote.