The system can be set to prevent the confirmation of contracts/advice notes/service jobs for specific customers unless a purchase order number has been entered. This requires that the option “Prevent Confirmation if missing order number?” is enabled on the “Customers” tab of Syrinx SP Configuration\System Options\Customers. The individual customers would then need to have the option “Order numbers Required?” enabled on the “Options” tab of their customer record in Syrinx SP\CRM\Customers.
If you want new Account Customers to have that option defaulted you can enable the “Order No Required?” option on the “Defaults” tab of Syrinx SP Configuration\Customer\Defaults.