WP: Check the Remember Me checkbox on WP Login Page automatically.

functions.php

/**
 * Check Remember me.
 *
 * Check the Remember Me checkbox on WP Login Page automatically.
 *
 * @since  1.0.0
 * @author AhmadAwais (https://AhmadAwais.com/)
 */
function aa_auto_remember_me() {
	add_filter( 'login_footer', function() {
		echo "<script>document.getElementById('rememberme').checked = true;</script>";
	} );
}
add_action( 'init', 'aa_auto_remember_me' );