Usage patterns
〈事〉は随意とするto leave something as optional / up to one's own discretion
Attendance at the information session is optional.
ご随意に〈動詞〉くださいplease feel free to do as you like
Please help yourself to drinks as you like.
随意に〈動詞〉to do something freely, at one's own discretion
Members may withdraw at their own discretion.