To enable GPC signal, consumers download a browser or extension that supports the signal. Similar to managing an ad-block extension, consumers can turn on the GPC signal for all websites they visit. If a website supports recognizing GPC, then it can register the browser request to Opt Out of Selling or Sharing Personal Info.
To check if GPC is enabled for your browser, simply go to https://globalprivacycontrol.org/. The site will check if the GPC signal is detected or not.