Add "Manual" or "Please Select" placeholder as a payment method choice for invoices
Currently, every invoice in WHMCS has a "payment method" option, populated with the available payment gateways the site has set up. I strongly believe that this default payment method choice should be made optional by adding a placeholder option here such as "Please Select", "Manual", "Customer Specified" etc. This is why:
Many businesses offer subscription products with automatic CC processing as well as custom products and one-time products (such as web design/development etc) that are quoted/invoiced manually. Currently, if a customer has a CC on file and automatic CC enabled, all invoices that are generated with the payment method set to "Credit Card" will be automatically charged on due dates. This is not the behavior many would want.
There should be clearly a control on a per-invoice basis to give the customer the freedom to choose payment method and pay on their own terms without defaulting to auto CC. Currently, there are only two ways to achieve this if the customer has CC on file: change the Payment Method option to something other than Credit Card from the admin area, such as "Paypal", "Mail in Payment" etc. But the problem is that this selected payment method will then show up under the Payment Method field on all of the customer's invoice pages and email notifications etc, potentially causing confusion for the customer (because it's probably not payment method they want to use). The other choice is to simply disable automatic CC processing for the customer, but this is apparently bad if the customer does have active subscriptions.
So please make the Payment Method choice optional by adding the placeholder. This makes sense because an invoice is just an invoice, a statement/bill. It should not be forced to select an actual payment method at the time of invoice generation. We don't see the "payment method" field on our Internet/phone/TV bills etc.