Definition (1):
Support activities refer to the activities in a firm that assist the firm as a whole by providing infrastructure or inputs that allow the primary activities to take place on an ongoing basis. This term is sometimes called staff or overhead functions.
Definition (2):
Support activities partially mean everything that helps run a business but really are not related to the product of the business. These activities can include the implementation of payroll procedures, indirect procurement systems, internal communications structures, etc. Some of these mentionable activities do not cost much at all to carry out.
The business leader can buy coffee that keeps her/his employees energized. S/he can buy her/his employees' soft drinks or give them an opportunity for hanging out during lunch with her/him once a week for keeping them happy as well as productive. Because most of us know this old saying “A happy worker is a productive worker.”
Support activities can contribute to the success of a business indirectly. Because they do not produce products and services for sale, but they make environments and systems for improved quality. Again, if a business entrepreneur or manager does not track these activities properly, it can lead to huge losses, and even become the downfall of her/his business.