HTTPS
HTTPS is HTTP carried over TLS: confidentiality, integrity, authenticity. It is the normal state of the web — browsers treat plain HTTP as an anomaly to be flagged.
In practice
Beyond encryption, HTTPS gates modern browser APIs: geolocation, push notifications, HTTP/2, and HTTP/3. Full implementation includes a blanket redirect from HTTP, HSTS to lock it in, and elimination of mixed content. A professional site no longer serves a single resource over an unencrypted connection.