Go to Settings > General > Software Update > Download/Install
General Rule: When presented with an update to iPadOS go ahead and install. The only exception is when Tech Help has specifically communicated that you should not update.
Important Note: Occasionally SMA will require that iPads be on a minimum iPadOS version allowing for enough time to update. If an iPad is not updated additional restrictions will be set and the wallpaper changed (see Yellow Screen of Despair) until the minimum version is installed. After updating it may take up to 24 hours before the setting to change the wallpaper will reappear in Settings (it does not go back to what it was automatically).