I want to send an invoice to clients so that at the bottom of the invoice, there's an option to click here to make a payment. The invoice may be a .pdf document attached to an email.

That link sends them to a specific web page, but I want to have some information on the invoice that is transfered to the Website like Name, address, etc...

How do I go about coding & organising this.
If possible, I would prefer NOT TO USE COOKIES, but if that can't be avoided, then, so be it.

Any help appreciated.