When you connect your Ontraport account to XOSync in Step 1, the app will automatically generate a new field section and 4 new fields into your account.
Xero Contact Key - This is a Text field that will be automatically populated with your contact's unique identifier from Xero. By having this information in the Ontraport Contacts it enables the two systems to stay connected. When any contact information on this contact is updated in Xero it will automatically update this contact in Ontraport. This is the variable that needs to pass in the View Invoices link to find the correlating contact in Xero.
Xero Outstanding - This is a Price field that updates daily based on changes to invoices, credit notes and contacts in Xero. If your contact has any amount payable the aggregate amount for all that they owe will appear here.
Xero Overdue - This is a Price field that updates daily based on changes to invoices, credit notes and contacts in Xero. When your contact has an amount owing that is passed the due date of any invoice, the aggregate amount will appear here.
Xero Overdue - This is a Date field that updates daily based on invoices, credit notes and contacts in Xero. It will updated with the date of the last invoice in Xero for that connected contact.
Having these fields in your Ontraport account will enable you to trigger automation based on their values changing.
Checkout some of the XOSync Campaigns available in the Ontraport Campaign Marketplace for some ideas.