A personal reference is someone who you have not worked with but can describe your values, integrity, character and goals. You can select personal references from many parts of your life, including volunteering, school, personal associations and longtime friendships. You should avoid listing family members or your spouse as personal references, as they might be perceived as biased. You want to choose personal references who have known you at least one year, think positively of you, are able to communicate well and are available on short notice.
A professional reference is someone who has worked closely with you for at least six months within the past seven years. They are usually a coworker or immediate supervisor, but can also be a department head, higher-level manager or client if they interacted with you regularly. You should choose professional references who can speak directly about your daily work habits, performance, work ethic and professional goals so that the employer can get a clear idea of who you are in the workplace and how you contributed to the work environment.