TELUS Health Companion uses the GPS functionality that is built into your Apple Watch. As long as you are in Canada where there is cellular service, your watch should be able to pick up your location coordinates.
You will also have to make sure your location services setting “allows” TELUS Health Companion to use your location.
If you require emergency support, the operator will be able to dispatch first responders to your location. Rest assured that the operator will always attempt to verify your location verbally first before dispatching first responders to your GPS coordinates.