A bug report is a document created to inform developers about issues or errors in a software application. It typically includes details such as the steps to reproduce the problem, the expected outcome, and the actual outcome. This information helps the development team understand and fix the issue efficiently. Bug reports are essential in the software development process, as they contribute to improving the quality of the product. They can be submitted by users, testers, or developers themselves. Tools like JIRA or Bugzilla are often used to track and manage these reports throughout the development cycle.