Branding themes are invoice templates you set in your Xero settings.
How to set Airwallex as a default payment service for a specific branding theme?
When setting up the Xero Invoice Payment connection, you can choose which branding themes you want to use Airwallex as the default payment service for. Your selection will be displayed in Xero under “Settings” -> “Payment services”. You can also make changes later by clicking “Manage themes”.
What happens when you set Airwallex as a default payment service?
If you set Airwallex as a default payment service for a specific branding theme, Airwallex will be automatically selected the next time you create a Xero invoice with that branding theme. To view or change the selection for a specific invoice, click on “Manage online payments.