-H/--header (HTTP) Extra header to use when getting a web page. You may specifyany number of extra headers. Note that if you should add a customheader that has the same name as one of the internal ones curl woulduse, your externally set header will be used instead of the internalone. This allows you to make even trickier stuff than curl wouldnormally do. You should not replace internally set headers withoutknowing perfectly well what you're doing. Remove an internal headerby giving a replacement without content on the right side of thecolon, as in: -H "Host:".
curl will make sure that each header you add/replace get sent withthe proper end of line marker, you should thus not add that as apart of the header content: do not add newlines or carriage returnsthey will only mess things up for you.
See also the -A/--user-agent and -e/--referer options.
This option can be used multiple times to add/replace/remove multi-ple headers.