Codecov is a code analysis tool that helps users manage and compare code coverage reports, which indicate which lines of code have been executed by a test suite. Unlike testing tools, Codecov does not run tests but analyzes the coverage data they produce. It supports various programming languages and can integrate with tools like Mocha, Nyc, and Jest to generate coverage reports. Users can set up accounts with Codecov and Codefresh to automate the creation and viewing of code coverage reports upon committing to a Git repository. By configuring a Codefresh pipeline, users can connect to a container registry, run tests, and generate coverage reports, which are then uploaded to Codecov for detailed analysis. The tutorial provides step-by-step guidance on setting up these integrations, enabling developers to easily track and visualize code coverage metrics in their projects.