HTTP is by far the most commonly used protocol by libcurl users and libcurl offers countless ways of modifying such transfers. See the HTTP protocol basics for some basics on how the HTTP protocol works.
Doing HTTPS is typically done the same way
as for HTTP as the extra security layer and
server verification etc is done
automatically and transparently by default.
Just use the https://
scheme in the URL.
HTTPS is HTTP with TLS on top. See also the TLS options section.
See using Proxies with libcurl​