Give the Right Audience Access to Chatter Posts

Users can change which users or groups can view a post. Changing an audience on a post can share it with more people for added input, or restrict visibility to make sure that confidential information only reaches the right users.

Where: This change applies to Salesforce for Android and Salesforce for iOS version 18.0, in all editions except Database.com.

How: Each user can edit their post visibility inside the publisher.

In the Chatter publisher there's a dropdown menu beneath user name to choose the right audience for a  post. You can edit this setting after publishing a post.