Your customers do not need to be active in Buildertrend to receive an invoice, and they are able to pay you via email, too.

They do not have to be an active user in Buildertrend to receive an invoice if you are set up for online payments. You have the ability through the Owner Invoices tab to invoice your customer without them being active.

When you create an owner invoice and choose Save and Release, it will give you the option to enter an email address where you want that invoice sent. Or, it will ask you to notify the owner, which would then send the invoice to the email associated with the customer's information. 

From that point, the recipient will have an email containing the invoice and will have the ability to pay you online after they have set up an account with WePay for the online transaction.