See Book a ride with the Google Assistant (Google Keyword blog) for more details
"After announcing some updates to the Google Assistant user experience yesterday, today Google is rolling out a new way of booking rides with your voice — or at least getting most of the way there. Starting this week, you’ll be able to say “Hey Google, book a ride to” or “Hey Google, get me a taxi to” your destination.Google Assistant now helps you compare ride-hailing prices and summon a car -- The Verge
Assistant will then respond by listing off price estimates and current wait times for Uber, Lyft, Ola, Grab, GO-JEK, “and many more” ride-hailing apps, according to Google. You can avoid the longer list and specify your preferred service by using its name when requesting a ride. This works on Android, iPhone, Google Home, and all other smart speakers that have Assistant built in. Support for smart displays is coming soon."