Here and here is the doc to do that.

Here is the doc to do that.

The Content compliance setting enables you to specify what action to perform for messages based on predefined sets of words, phrases, text patterns, or numerical patterns. The content compliance setting scans messages for content that matches one or more rules that you configure within the setting. You can choose whether these messages are rejected or delivered with modifications -- for example, to notify others when the content of a message matches the rules that you set.