The Product Backlog is a dynamic and prioritized list of items that represent the project's requirements. It serves as a single source of truth for what needs to be done. The Product Owner continuously refines and updates the backlog based on feedback, changes, and new insights. Items in the backlog are typically user stories, features, and technical tasks.
The Sprint Backlog contains the subset of items from the Product Backlog that the Development Team commits to completing during the sprint. It's a plan that evolves as the team learns more about the work during the sprint. The Development Team updates the Sprint Backlog daily during the Daily Scrum, adjusting tasks and priorities as needed.
The Increment is the sum of all completed backlog items at the end of a sprint. It's a potentially releasable product version, which means it meets the team's Definition of Done. Each increment should add value and be a foundation for subsequent work. The Product Owner decides whether to release the increment to stakeholders.