What is Google Tag Manager?
Google Tag Manager is a service that allows you to install tags in your website’s head tag without modifying your website code.
Tags are code snippets that allow you to track user behavior on your site. Many marketing and measurement tools require you to add these tags to your website’s head tag to monitor how visitors land on your site and what they do during their visit.
Ideally, you’d need to modify your website code to install the tags. However, with Google Tag Manager, you only need to upload the tag to Google Tag Manager, and Google will add it to your site.