HTTP (HyperText Transfer Protocol) exchanges requests and responses between a client and server. HTTPS protects that exchange with TLS. Joomla uses HTTP for pages, images, form requests and APIs.
Requests and responses
A request contains a method, target and headers, plus a body when needed. A response includes a status, headers and data. GET normally retrieves a resource, while POST submits data for processing. Loading HTML successfully does not prove every Joomla form works.
What HTTPS provides
TLS protects data confidentiality and integrity in transit and authenticates the server through its certificate. HTTPS does not guarantee that a site owner is trustworthy or fix application vulnerabilities.
HTTP/1.1, HTTP/2 and HTTP/3 organise communication differently while retaining core concepts such as methods and statuses. HTTPS alone does not identify the HTTP version in use.
HTTPS in Joomla
First configure a valid certificate and HTTPS handling on the hosting platform. Then coordinate HTTP redirects, Joomla settings and any reverse proxy configuration. Check for loops and mixed content, where a secure page requests resources through HTTP.
After migration, test login, forms, cookies, images, APIs and both Joomla language versions. Update integration settings where they depend on the URL scheme.
Summary
HTTP defines web communication, while HTTPS protects the connection. A Joomla website needs checks across the server, application and external integrations.