Supporting documentation provides evidence of your skills, accomplishments and knowledge, backing up the claims made in your portfolio narrative.
Appropriate documentation may include:
Completion certificates documenting relevant training and workshops
Professional licenses or certificates
Membership and activity in professional organizations or in labor relations
Awards, citations, or other examples of achievement recognized by others
Books, papers, or manuals written, edited or significant contributions made
Experiences as a lecturer, panelist, instructor, etc.