PHP Developer Required to ass a basic function to exisinting system!!

I run various sites which sell eBooks and digital delivery is managed from one a single host using PHP and a MySQL Database.

It works well -> Once PayPal payment has been completed it triggers order.php to generate a one-off password which is logged in the MySQL table and an email is sent to the customer.

Sometimes, however, the email doesnt make it to the customer and I have to send it manually.

I would like an option (ideally an entirely seperate php file) where I can enter any email address I like and have the same function as order.php generate the code and email it for a single use.

I hope this is fairly clear, it's a straightforward job as I can see the code - but I have no idea what the syntax for PHP is for what I want it to do!

Any questions, please email me.

Looking at the code, this should take < 30 mins from start to finish :)