While the whole cross-functional agile team collaborates on the backlog, the product owner is in charge of it. The product owner (or product manager) is usually in charge of managing and maintaining the product backlog. However, it is often recommended that different members of the cross-functional team submit items to the backlog. It's worth mentioning here that, depending on a team's agile strategy, many backlogs with various objectives and owners may exist. A sprint backlog, for example, is held by the delivery team under the Scrum technique.