When you use a certification authority system to generate your own digital certificates, it will use the X509 standards to create the certificates. These standards include some basic information about the digital certificate, such as who issued the certificate, the certificate version number, and how long the certificate is valid. There are also other structures included as part of these standards which are required.
X509 Standards Helped Resolve Digital Certificate Compatibility Issues
In the past, organizations used all different types of digital certificates. This caused problems when trying to share information between multiple sources. You would need to obtain a digital certificate from the issuer, which may be someone entirely different than the person, who sent you the document or data in the first place. As a result, the X509 standard was created to resolve compatibility issues between certificate issuers.