"Volunteer activities" refers to tasks or actions that individuals undertake willingly and without being paid to help others or contribute to a cause. Full definition
For example, provide 8 - 10 paid hours per month to participate in volunteer activities. (entrepreneur.com)
Examples of volunteering activities include working on nursing homes, serving in homeless shelters, helping out in blood banks and organizing blood - letting activities in your school. (rnresume.net)
Additionally, do not confuse relevant volunteer activities with hobbies; work can still count as such even if you did for free. (resume-now.com)