The device has an integrated antenna under the front cover. Please consider that when mounting the device so that you leave enough free space in front of the device.
The device is not rated for outdoor use without additional protective casings. As long as you use a plastic casing the built in antenna will be enough to get cell coverage in most areas.
When using an IoT platform to monitor the device you can see the signal strength in the MQTT-telemetry. For Telenor MIC, the signal strenght is visualised by an icon that indicates the signal quality.