The login_form_{$action} WordPress PHP action fires before a specified login form action. The dynamic portion of the hook name, $action, refers to the action that brought the visitor to the login form.
Usage
add_action('login_form_{$action}', 'your_custom_function');
function your_custom_function() {
// your custom code here
}
Parameters
None
More information
See WordPress Developer Resources: login_form_{$action}
Examples
Adding a message before the login form
Display a custom message before the login form.
add_action('login_form_login', 'your_custom_message_function');
function your_custom_message_function() {
echo '<p><strong>Welcome!</strong> Please enter your credentials to log in.</p>';
}
Displaying a message before the lost password form
Add a message to guide users before the lost password form.
add_action('login_form_lostpassword', 'your_lost_password_message_function');
function your_lost_password_message_function() {
echo '<p>Forgot your password? No worries, enter your email and we\'ll help you reset it.</p>';
}
Adding content before the registration form
Display custom content before the registration form.
add_action('login_form_register', 'your_custom_registration_content_function');
function your_custom_registration_content_function() {
    echo '<p>Join our amazing community by creating a new account below.</p>';
}
Displaying a message before the password reset form
Add a message to guide users before the password reset form.
add_action('login_form_resetpass', 'your_password_reset_message_function');
function your_password_reset_message_function() {
    echo '<p>Enter your new password below to reset your account password.</p>';
}
Adding a message before the logout action
Display a custom message before the logout action takes place.
add_action('login_form_logout', 'your_custom_logout_message_function');
function your_custom_logout_message_function() {
    echo '<p>Thank you for visiting! You are now being logged out.</p>';
}