Customer Sync Rules
Define Search Parameters: Set search preferences to match HubSpot companies with Xero customers using specific fields, reducing duplicates by verifying existing records. Select a field (such as Company Name) from a drop-down in HubSpot for the customer sync rules and select a corresponding field (Customer Name) from the drop-down in Xero. Click "Save".
Enable Primary Sync Contact
This feature is essential for businesses dealing directly with consumers, allowing seamless addition of individual contacts from HubSpot to Xero as customers when there's no associated company. Therefore, if this is the case, check “Enable Primary Sync Contact.” From the "HubSpot Contact Identifier" dropdown menu, select the HubSpot field that uniquely identifies your contacts, such as person name and email.
From the "Xero Contact Field" dropdown menu, select the corresponding field in Xero that should be used to match and identify the same contact. This should also be a unique identifier like an email address or customer number in Xero. Click "Next".
Select one of two options for handling the contact ID or account number when a customer is created in Xero: You can select whether Xero creates the contact ID or takes the account number from Hubspot when creating new customer records.

Xero Customer Number Field: This option is conditional based on the previous selection. When using primary contact sync to search customers, store the autogenerated contact ID in the company field property and in the contact field property.
Select the HubSpot field that will store the value of the auto-generated Xero contact ID. You can also choose not to store it anywhere in HubSpot. It helps with integrated tracking, or you can opt not to retain this number within HubSpot for a cleaner dataset.
Or you can choose to take the account number from HubSpot, for which you need to select the company and contact account number fields.
After you have selected the parameters, scroll down and click "Save".