Unusually, this is for iPhone users only.
If you are driving to an appointment and want to let the others know when you will get there, it’s time wasting to stop the car and engine in order to send a text. However, you can automate this with Apple Maps (but not other mapping services).
Plan a route and select car as your method of transport. Start the directions and swipe up from the bottom of the screen to tap ‘Share ETA’. Now select the contacts to share your arrival time with.
Those contacts who are using Apple Maps will see updates. Others will get text messages.
You can also set places you go to frequently as favourites. When you start moving thatw ay, they will get updates.