As with the current cities where Verizon is working on 5G (Chicago, Denver, Minneapolis, St. Paul, and Providence), the 5G service is limited in scope and has been made available in "dense, urban areas where people tend to congregate," such as public parks, monuments, college campuses, and stadiums.
Verizon's press release has specific listings of the areas where 5G connectivity is available in each city.
Verizon has said that it plans to bring its 5G service to more than 30 cities in 2019, including Boston, Charlotte, Cincinnati, Cleveland, Columbus, Dallas, Des Moines, Houston, Kansas City, Little Rock, Memphis, Phoenix, San Diego, and Salt Lake City.
Using Verizon's 5G network in 2019 requires a 5G-enabled device, and those are limited at this time. 5G works on the LG V50 ThinQ 5G and the Samsung Galaxy S10 5G, among other devices.
Apple's iPhones will not be able to connect to 5G networks until an iPhone that supports 5G is released. Apple is working on 5G devices and is expected to release the first 5G iPhone in fall 2020.