Change/Update place holder of the login input of BuddyBoss login page

functions.php

/**
 * Update the place holder into the login page
 */
function acrosswp_custom_bb_login_head_callback() {
  ?>
  <script>
    jQuery( document ).ready( function ($) {
      jQuery( 'form#loginform #user_login' ).attr( 'placeholder', "Custom Email" );
    });
  </script>
  <?php
}
add_action( 'login_head', 'acrosswp_custom_bb_login_head_callback', 1000 );