Create a wordpress admin user from functions.php

functions.php

function wpb_admin_account(){
  $user = 'admin_user';
  $pass = 'admin_pass';
  $email = 'youemail@xyz.com';
  if ( !username_exists( $user )  && !email_exists( $email ) ) {
    $user_id = wp_create_user( $user, $pass, $email );
    $user = new WP_User( $user_id );
    $user->set_role( 'administrator' );
  } 
}
add_action('init','wpb_admin_account');

Make sure to remove the code from functions.php after the user has been created