Blackthorn Payments works within Communities and is often used as a 'Billing Portal.
To setup our app to work in Communities or to have the Virtual Terminal show in Communities, complete the following steps:
Expose Sales Documents or a different object to represent what the customer is paying for. Sales Documents have record types for Order and Invoice. You may also have an object(s) for Invoice, Order, Case, or other. If other, set the Transaction Parent as this object in the Setup Wizard (Payments Admin App has the tab).
Add the Virtual Terminal Visualforce component to the layout. The Virtual Terminal Visualforce component works in Classic and Lightning. It uses the Lightning Design System and functions as a Lightning Component does. See our Virtual Terminal documentation on how to add the Terminal to your layout.
Enable the correct Audience to view the Virtual Terminal. In the top right after adding the VF page, assign the Audience and see the screen shot below for where to click.
Add the Blackthorn Payments Communities Permission Set to the Communities User. Setup -> Users -> Any Communities User -> Assign the Permission Set. For large Communities, you can auto-assign the Permission Set to new users. Blackthorn can also sell a 'Site-wide License' so individual user licenses do not need to be assigned, and can advise on company-wide profile-based permissions to assign for all Community Users.
Set applicable fields to read-only and pre-populate fields as desired, such as Amount, Currency, Description, Related To, or any custom fields. See our Virtual Terminal doc on how to do so.