How can I set referrer policy header for my site?

I want to set a referrer policy header for my apache site. I’ve added these two standalone lines in .htaccess to add an x-frame-header and referrer-policy-header:

Header always set X-Frame-Options "SAMEORIGIN"
Header always set Referrer-Policy "no-referrer-when-downgrade"

X-Frame header added but the Referrer header not added! Is there any reason for that?

Presumably you’ve not added one?