The create announcement button on the top right of the page (only available to Admins) allows you to send a company-wide announcement which will be sent both through email and as a notification on employees' Home pages.

The notification is written in the form of an email, with a subject line and a body. The subject line will be used as the header for the in-app notifications and the body as the details. Once an announcement has been sent, it cannot be deleted - be sure to thoroughly review the draft before clicking the save button which will send the announcement.