Google Tag Manager is a tag management system that allows you to quickly and easily update tracking codes and related code fragments collectively known as "tags" on your website or mobile app. Once the Tag Manager web snippet or mobile SDK has been added,  configure and deploy tag configurations from a web-based user interface. This reduces errors and avoids having to involve a developer every time a change is needed.

Setup and installation guide can be found here.

To access Google Tag Manager please follow the steps below.

1. Go to Google Tag Manager
   
2. Click the "Admin" tab and "User Management"
3. Click "New", fill in the information as follows and click "Add"