When you add a payment link to a Xero invoice, you enable your clients to pay their invoices online.
To add a payment page link to a Xero invoice:
In the AffiniPay web application, click Charge
For the account where you want to deposit payments click Actions > Show & Copy Page Link
Copy the link in the box that appears. You'll paste it in your Xero invoice
In Xero, add a custom payment link