Well literally, it's " to reach out" , is to stretch out to somebody and we often use it idiomatically to mean to reach out to somebody who needs help or somebody we want to help and give value to.

从字面上来说，to reach out 就是向某人伸出手，我们经常用这个习语表示向需要帮助的人伸出援手，帮助他人给他人一些价值。