Definition
SSL and TLS are cryptographic protocols that provide encrypted communication over networks. TLS is the modern successor to SSL (SSL is deprecated). When you visit https://, your browser and server negotiate a TLS connection. Certificates identify the server and enable encryption. TLS 1.3 is the current standard. The SSL certificate chain must include both the domain certificate and any intermediate CA certificates.
Use the tool: SSL Certificate Checker — check ssl/tls for any domain.