After logging into WordPress dashboard go to Appearance > Editor from the menu at the left hand side.
Now locate the functions.php file
The location to the file may look like : /home/username/public_html/wp-content/themes/currently_active_theme/functions.php
Make a local backup of this file in case anything goes wrong and you may need to revert to previous stable code.
click on it to begin editing it.
# Add async to all remaining scripts
return str_replace( ' src', ' defer="defer" src', $tag );
add_filter( 'script_loader_tag', 'js_async_attr', 10 );
Let me know firstname.lastname@example.org/skype-bpshbp if you have any Query