'Freewill Offerings' in the Bible

“Speak to Aaron and to his sons and to all the sons of Israel and say to them, ‘Any man of the house of Israel or of the aliens in Israel who presents his offering, whether it is any of their votive or any of their freewill offerings, which they present to the Lord for a burnt offering—

besides those of the sabbaths of the Lord, and besides your gifts and besides all your votive and freewill offerings, which you give to the Lord.