When and where you post your announcements will affect whether students can view them. You should attempt to make routine announcements; preferably within a designated channel (e.g. General). Be mindful when sending out an announcement, students will receive a “ping” every time, distracting them from whatever work they might be doing at that time. If you are interested in learning how to change permission settings and make announcements, we recommend checking our guide for Making Announcements in Microsoft Teams.