A Pull Request in Azure DevOps (formerly known as Visual Studio Team Services or VSTS) is a feature used for code collaboration and review in software development projects. It is a process that allows developers to propose changes to the codebase, and other team members can review, discuss, and approve those changes before they are merged into the main codebase. Pull Requests are commonly used in conjunction with version control systems like Git.

Here’s how the process generally works in Azure DevOps:

1. Create a Branch: Developers work on their changes in separate branches. These branches can be created directly in Azure DevOps or locally and then pushed to the remote repository.

2. Make Changes: Developers make changes to the code in their respective branches. These changes could be bug fixes, new features, or improvements.

3. Commit Changes: Developers commit their changes to their branches with descriptive commit messages explaining what the changes are.

4. Create Pull Request: Once the developers are ready to share their changes with the team, they create a Pull Request (PR) in Azure DevOps. They specify the source branch (the branch with their changes) and the target branch (usually the main/master branch).

5. Review and Discussion: Team members are notified of the new Pull Request and can review the changes. They can leave comments, ask questions, and provide feedback on the code changes. This collaborative review process helps improve code quality and catch issues early.

6. Iterate and Update: Based on the feedback received during the review, the developer can make additional commits to their branch, addressing the feedback and making necessary changes.

7. Approve and Complete: Once the reviewers are satisfied with the changes and the code has been thoroughly reviewed and tested, they can approve the Pull Request. Some organizations might require a certain number of approvals before a Pull Request can be completed.

8. Merge: After approval, the changes are merged into the target branch (e.g., main/master). Azure DevOps provides options to squash commits, preserve commits, or rebase the changes before merging, depending on the organization’s preferences.

9. Close Pull Request: Once the changes are merged, the Pull Request is closed. The changes are now part of the main codebase.

Azure DevOps provides a user-friendly interface for managing and visualizing the Pull Request process, including tracking approvals, comments, and the overall status of the review. It helps streamline collaboration among developers and ensures that code changes are thoroughly reviewed before being integrated into the main codebase.