Hi Bill, apologies for the late reply. If you mean the Status update below the cover photo on your profile page you can click on the link which highlights in green to "add a status" and you can edit it by clicking on the pencil, which says "Update your status". You can not add anything below on somebody's status, if you wish to comment about it, it is probably best to post on their profile page or to private message them.
Hope that helps.