Simply tap on a marker. On the screen that pops up, under "my location" or the marker's type, you will be able to see the three words that identify it, next to the coordinates. These are separated by full stops (periods).
Communicate these three words clearly to the emergency services to guide them to your location. It can be hard to stay calm and read out long coordinates over the phone. With what3words, you won’t have to worry about it anymore.