Use issues to track ideas, enhancements, tasks, or bugs for work on GitHub.
Many projects collect user feedback via a central bug tracker. GitHub's tracker is called "Issues," and can be used with every repository.
Issues can act as more than just a place to report software bugs. As a project maintainer, you can use Issues to organize tasks you'd like to accomplish, such as adding new features or auditing old ones. You can associate issues with pull requests, so that when you merge a pull request, your issue will automatically close. If you're using a project board to track and prioritize your work, you can see what project board an issue is a part of by viewing the project board section within the issue.
You can opt to receive notifications whenever an issue is updated with a new comment so that you're always in the loop. Issues can also be assigned to other users, tagged with labels for quicker searching, and grouped together with milestones.