When working within a Team, messages are created and sent using the entry box at the bottom of the feed within the Posts tab. By default, these messages are created using Conversations.
Sometimes, you may need to communicate important information or grab the attention of your Team members. This can be accomplished using an Announcement rather than the default Conversation. Announcements allow for customizing the message with various formatting options, including adding a background color or image and providing a styled headline and subheading.
Announcements are only available within Teams Channels and not within individual or group Chats. View instructions on sending Channel Announcements.