Want additional dashboard widgets to give some info to your clients? Use this snippet:

 
add_action('wp_dashboard_setup', 'my_custom_dashboard_widgets'); 
function my_custom_dashboard_widgets() { 
 
global $wp_meta_boxes; 
wp_add_dashboard_widget('custom_help_widget', 'Theme Support', 'custom_dashboard_help'); 
} 
function custom_dashboard_help() { 
echo '<p>Welcome to Custom Blog Theme! Need help? Contact the developer <a href="mailto:yourusername@gmail.com">here</a>. For WordPress Tutorials visit: <a href="http://www.wpbeginner.com" target="_blank">WPBeginner</a></p>';}