I have quickly put together a custom code that may help you with this.
Add this custom code to the functions.php in your theme/child theme directory (copy from line 3 only!). Before editing, please make sure to have a full site back-up just in case!
This runs an auto-populate feature when the user focuses the input the first time.Best,
If you like my products, don't forget to rate them on codecanyon :)