How can I pass referrer header from my https domain to http domains?

As mentioned is this answer there is a new method of doing this: Referrer Policy/meta tag.

See spec and example in this q&a.

I also had this same problem. I solve by adding meta tag like below and it will be work only in Chrome and Safari.

<meta name="Referrer" content="origin">

Sadly you can not referrer on HTTPS to sites using HTTP. You can however do HTTPS to HTTPS or HTTP to HTTPS.

SOURCE

Clients SHOULD NOT include a Referer header field in a (non-secure) HTTP request if the referring page was transferred with a secure protocol.

A work around would be to use a internal redirect script that rather than directing linking out to the visitor on the HTTPS you redirect to HTTP and then it redirects out.

For example:

<a href="http://www.yours.com/out.php?www.other.com">www.outboundsite.com</a> but this wouldn't use the original referrer.

Another possibility is using trackbacks rather than referrers and as far as I know this works in HTTPS.