The core of Asterisk provides a basic HTTP/HTTPS server.
Certain Asterisk modules may make use of the HTTP service, such as the Asterisk Manager Interface over HTTP, the Asterisk Restful Interface or WebSocket transports for modules that support that, like chan_sip or chan_pjsip.
The configuration sample file is by default located at /etc/asterisk/http.conf
A very basic configuration of http.conf could be as follows:
That configuration would enable the HTTP server and have it bind to all available network interfaces on port 8088.
See the sample file in your version of Asterisk for detail on the various configuration options, as this information is not yet automatically pushed to the wiki.