If you want to be able to release a "Purchase Order" without it going through the Compliance Check process because the Vendor you are using does not require any certification, then open the "Vendor" card and tick the Exclude from Vendor Compliance toggle. This will skip the check process and will allow any "Purchase Orders" to be released without requiring a valid certificate.

Any Vendors excluded from Vendor Compliance will not be shown in the "Vendor Compliance Documents" Vendor No. lookup list when assigning the Vendor, as you cannot assign an excluded Vendor to a Compliance Document.  

If the business needs change and you do wish to store certificates against them in the future, ensure the toggle is switched 'off' before assigning them on the "Vendor Compliance Documents" page. 

Note - In the instance you had a previous certificate assigned but have since marked the vendor to Exclude from Vendor Compliance, it will retain the assignment entry in "Vendor Compliance Documents", it just won't check for these once excluded.