Notifications let you know if you missed a call or IM, or anything else when you’re not actively using the Skype for Business (Lync) app. Notifications also let you know if there’s an issue with the app, or if you need to take action. You can set up notifications so they display as a banner or alert message, and a badge application icon. You can also have a sound play when a notification is received.
You can set how to display notifications from your iPad Settings.
From the Setting app, tap Notifications, and select Skype for Business (Lync). Then select how you want notifications to be indicated.