The phrase "manager name" refers to the name or title given to a person who is responsible for leading and supervising a group of employees or a particular department within an organization. Full definition
Dear (Hiring Manager Name): I am writing to express my interest in your current opening for a (Position Title). (resumemycareer.com)
Dear «Hiring Managers Name», if you don't have the name don't even bother saying something like dear recruiter or dear anything. (resumetemplatesformac.com)
John Conyers III, a Detroit hedge fund manager named as a possible successor to his scandal - rocked father, Rep. John Conyers, was arrested in Los Angeles this year on suspicion of domestic violence, but prosecutors declined to charge him. (nystateofpolitics.com)