Every service provider (carrier) will furnish a device with a contract plan or you can purchase a compatible device on your own through eBay or Craig's List and go with a no contract plan.
Here's a page where Verizon shows their "mobile hotspots"
https://www.verizonwireless.com/internet-devices/No matter where you take them or turn them on (as long as there's a cell signal) the hotspot (wireless router) will connect to network provided by the carrier. Once that happens you can get "online". No changes are necessary on your part after the initial setup. If your computer doesn't connect automatically you may need to scan for the WiFi networks available and connect to the one your device is broadcasting. It's much more secure and safe than connecting to a public WiFi network.
I don't believe the 5G option is practical right now as it hasn't been completely implemented yet and it's range is much less than 4G service which can be fast enough to watch streaming videos. The more data you use, the more it costs.
Don Ford
2004 Safari Trek 31SBD (F53/V10 20,500GVW)
'09 HHR 2LT or '97 Aerostar MiniVan (Remco driveshaft disconnect) for Towed vehicles
BlueOx Aventa II Towbar - ReadyBrake Inertia Brake System