Don’t mess around with nasty codes in your theme header & footer template files. Use this absolutely free plugin and you can automatically inject codes (adsense, tracking, etc) and snippets into all of your wordpress posts/pages or specific categories and locations.

💪🏼 You can download this plugin here for free: https://wordpress.org/plugins/header-footer/
*you can also add this plugin directly from the wp-admin as seen in the video.