Use Emergency SOS via satellite on your iPhone
iPhone displays 
when you’re outside cellular and Wi-Fi coverage; Emergency SOS via satellite may still be available.
Important: If an Emergency SOS via satellite session has been made and you don’t need emergency services, don’t hang up. Wait until a responder answers, then explain that you don’t need help.
Note: iPhone satellite features are available on supported models. Emergency SOS via satellite isn’t available in all countries or regions. See the Apple Support article Emergency SOS via satellite availability.
Connect to Emergency SOS via satellite on your iPhone
Try calling 911 or emergency services even if your normal cellular carrier network isn’t available.
If your carrier’s cellular network is unavailable, iPhone displays
and attempts to route any emergency calls through other networks, if available.If the call doesn’t go through, tap Emergency Text via Satellite to text emergency services.
You can also go to the Messages app and text 911 or SOS, then tap Emergency Services.
Tap Report Emergency and follow the onscreen instructions.
Important: To help you connect to a satellite, make sure to hold your phone naturally in your hand—you don’t need to raise your arm or hold your phone up, but make sure your phone has a clear line of sight to the sky. If you’re under heavy foliage or surrounded by other obstructions, you might not be able to connect to a satellite.
After you’re connected, your iPhone starts a text conversation by sharing important information including your Medical ID and emergency contact details (if you set them up). It also shares your answers to the emergency questionnaire, your location (including elevation), and your iPhone’s battery level. In addition, you can also choose to share the information you send to emergency services with your emergency contacts.
Try the demo before going to a remote location
If you’re planning a trip to a remote location, you can create your Medical ID, add emergency contacts, and try the Emergency SOS demo before you go.
Go to Settings
> Emergency SOS on your iPhone.Scroll down and tap Try Demo.
Note: The Emergency SOS demo doesn’t start a call to emergency services.