voluntary
adjective
uk/ˈvɒləntəri/ usdone, made, or given without being forced or paid:
Currently, recall of products is voluntary.
Any staff reductions will be made on a voluntary basis.
voluntary service/work She does voluntary work in several hospitals.
used to describe an organization that is supported by people who give their time and money to it without being paid, and that exists to help other people:
He works in the voluntary sector.
It is an independent voluntary organisation providing money advice.
voluntarily
adverb
Did she leave voluntarily?