Google Analytics is a free web analytics service that offers basic analytical tools and statistics used for search engine optimization (SEO) and marketing. The performance of a website and information about its visitors are monitored and analyzed using Google Analytics. 

In addition to identifying the most popular sources of user activity, it can provide valuable information about the effectiveness of a company's marketing initiatives and campaigns, keep tabs on how customers complete tasks (such as making purchases or adding items to their shopping carts), identify trends and patterns in customer behavior and gather demographic data.

How Does Google Analytics Work? 
To collect user data from every website visitor, Google Analytics employs the usage of page tags. JavaScript page tags are added to each page's code. Google's data gathering servers get data from each visitor via the use of this tag, which is embedded in the visitor's browser. Customizable reports may then be generated by Google Analytics to monitor and show data on the website traffic, the average session lengths, sessions by route, page views, and more.

To collect visitor information, the page-tag acts as a  web beacon or web bug on the page. The system, however, cannot gather data from users who have deactivated cookies since it is reliant on cookies. 

Google Analytics has capabilities that allow users to see how visitors interact with their websites over time. Data gathering, analytics, tracking, visualization, reporting, and interaction with other applications are all made possible via the use of features. The following are only a few examples:

Tools for data visualization and monitoring, like dashboards, scorecards, and activity charts that illustrate data changes over time. 
Filtration, modification, and analysis of funnels of data.
Application program interfaces (APIs) for data collecting.
Actionable insights, intelligence, and identification of anomalies.
Segmentation for the purpose of analyzing subsets of data, such as conversions.
Tailor-made reports for advertising, audience acquisition, audience behavior, and conversion.
Sharing and conversation through email.
Integrations with Google Ads, Salesforce Marketing Cloud, Google Data Studio, Google Optimize 360, Google AdSense, Google Optimize 360, Google Display & Video 360, Google Search Ads 360, Google Search Console, and Google Ad Manager.
For each website, a unique set of metrics may be shown in the Google Analytics dashboard, with the option for users to store profiles for future use. Content summary, keywords, referral sites, visitors review, map overlay, and traffic streams overview are some of the categories that may be tracked.

In addition to being accessible via the Google Analytics website, a plugin or a widget for integrating the dashboard onto other websites is also made available. Independent vendors also provide customized Google Analytics dashboards, which may be customized to meet specific needs.