Sprint backlog is created during the Sprint Planning which happens at the beginning of new sprint. In Sprint Planning, the Scrum Team identifies the User Stories to be completed for that particular Sprint and then with the help of Product Owner understands the User Stories and puts them in the Sprint backlog.

Who decides sprint backlog?

The sprint backlog is a list of tasks identified by the Scrum team to be completed during the Scrum sprint. During the sprint planning meeting, the team selects some number of product backlog items, usually in the form of user stories, and identifies the tasks necessary to complete each user story.

Who creates backlog?

The Product Owner (PO) “owns” the product backlog on behalf of the stakeholders, and is primarily responsible for creating it.