Yes, we will accept payment via PayPal.
We typically issue invoices with the expectation of payment via check, because we do not pay processing fees on checks, but we will enable other forms of payment on request. PayPal is one of those alternative methods.
To make the request, please reply to the email notice you receive with the link to the invoice. Tell us if you want to enable PayPal for one-time use on that invoice... or for future invoices, as well. We will check a box, re-save the invoice and send you an update notice that PayPal is enabled.