Google Tag Manager (GTM) is a tool which provides a user-friendly interface to implement tags and pixels on your website, such as Facebook pixels or AdWords conversion tracking. By using GTM you can implement a wide variety of coding scripts, tags and code snippets that you would otherwise need to install on your website. GTM makes implementing and changing tags easier since they are all stored in one place.
With GTM, you can track a number of actions on your website, such as clicks on the menu, clicks on call-to-action (CTA) buttons or form completions. You can see similar data with Google Analytics, but it is not as detailed as the data from GTM.