See Transit Info and Calculate Travel Time in Maps App for Mac and iPhone/iPad
Open the Maps app, touch the info button at the bottom right, and choose transit.
For directions, enter the address or place in the search bar and then touch the bus icon next to the dropped pin. You’ll then see bus routs, rail lines, and more that you can take as well the estimated travel time. (Scroll up to see even more specifics about the route.)
Enter the address or place in the search bar and then click “Transit.” Indicate when you plan to leave and then choose the combination of transit options that works best for you.