X.509 certificates are digital documents that use a digital signature to bind a public key with an identity, ensuring the authenticity of the server and encrypting information being exchanged. They play a crucial role in secure communications and are widely used across websites, VPNs, Wi-Fi networks, and IoT devices. Generating X.509 certificates typically involves creating a key pair (private and public keys) and then creating a Certificate Signing Request (CSR), which is submitted to a certificate authority (CA) for signing. WorkOS offers an easy way to manage certificates through its Admin Portal, allowing automatic updates of expiring X.509 certificates.