Definition (行動)
To do something on your own initiative means to plan and decide to do it yourself without being told by anyone else.
自作主張，自行决定
She started organizing a community clean-up day on her own initiative.
她主動組織了一個社區清潔日。
He contacted the media on his own initiative due to concerns about the company's policies.
他因為對公司政策的擔憂，主動聯繫了媒體。
The manager praised the team member for addressing the issue on their own initiative, without being asked.
經理表揚了這位團隊成員，因為他們在沒有被要求的情況下主動解決了問題。