When you connect your Payhawk account to Xero, your available Xero tracking categories are automatically imported.
If you update your Xero tracking categories after the connection between the two systems has been established, you have to manually update that data in Payhawk.
Updating Xero categories in Payhawk
To manually update your tracking categories in Payhawk:
In the Payhawk web portal, go to Settings > Expense fields.
Below Built-in fields, select a Tracking Category.
Click on Update from Xero.

Editing or deleting existing tracking categories
You can edit or delete tracking categories only in Xero as the accounting system is the source of truth. The updated values will be displayed after you manually sync the integration from Settings or when you click on the Update from Xero button.
Making a tracking category available to another entity
In a multi-entity group, each entity syncs its tracking categories from the Xero organization it’s connected to, so a category and its values appear only for the entities whose Xero organization contains them.
This is why an entity can be missing from the entity visibility list of a synced custom field, because the category does not yet exist in that entity's Xero organization. You can't add it from the visibility settings in Payhawk alone.
To make the field available for that entity:
In Xero, open the organization connected to the entity that needs the field.
Create the tracking category, using the same name as the existing one. Payhawk matches synced tracking categories by their label.
In the Payhawk Web Portal, go to Settings > Integrations > Xero.
Click on the three-dot menu and select Manually sync to manually sync the Xero integration.
Refresh the page. The entity now appears and you can set its visibility.