HaloPSA is a professional services automation (PSA) software designed primarily for managed service providers (MSPs). It is a centralized platform for managing all business operations within an MSP or IT department. Kindly note that this integration is available from build 11.4.2535.0.
After the integration is set up, you will need to map each client in HaloPSA to its corresponding customer in Endpoint Central MSP.
customer_name.
customer_name field is sufficient to fetch and map computer details. Optionally map serial number, computer name, and IP address for easier identification and reference during import. This ensures assets from Endpoint Central MSP are correctly synced and mapped to the customer in Halo PSA.

Once the integration is saved, to configure the asset sync kindly follow the steps mentioned in the document.
Select the checkbox "Log helpdesk requests from agent tray icon to HaloPSA" such that help desk tickets raised from Endpoint Central MSP automatically flow into HaloPSA.
This helps unify service requests so technicians can track, respond, and resolve issues from a single console.
Once integrated, customer mapping from HaloPSA will now automatically sync with Endpoint Central MSP. You can also trigger a manual sync from the Endpoint Central MSP's HaloPSA Integration Summary page using the "Sync now" option.
You can update the URL, Client ID, and Client Secret in the "Modify" section if needed.
Once these steps are completed, the integration will allow for customer mapping and asset posting, as well as ticket creation (for on-premises setups)

If you face any issue, while integrating HaloPSA with endpoint Central MSP refer here.