How does your customer know the certificate in their hands is genuine?

Most certificates are only as trustworthy as the stamp on them — and a stamp can be copied. A sturdier approach is to derive a digest from the document's own content and store it with the signature: if the content changes afterwards, the digest no longer matches, and a machine says so rather than a person. For this to reach the customer, verification must not require an account; a verification page behind a login is a certificate nobody verifies. In SenSight QMS the QR code on the certificate opens a page with no sign-in: it shows whether the signature is still valid, who signed and in what capacity, and the digest. The page opens in the language the document was issued in.