Google Tag Manager is a tag management system (TMS) that allows you to quickly and easily update measurement codes and related code fragments collectively known as tags on your website or mobile app. Once the small segment of Tag Manager code has been added to your project, you can safely and easily deploy analytics and measurement tag configurations from a web-based user interface.Google Analytics
Google Analytics is Google’s analytics tool that helps website and app owners to understand how their visitors engage with their properties. It may use a set of cookies to collect information and report site usage statistics without personally identifying individual visitors to Google. The main cookie used by Google Analytics is the ‘_ga’ cookie. In addition to reporting site usage statistics, data collected on Google properties by Google Analytics may also be used, together with some of the advertising cookies described above, to help show more relevant ads on Google properties (like Google Search) and across the web and to measure interactions with the ads we show.