With Betternet, you can select a wide range of servers to connect to. The servers available to you may differ depending on if you're using the free or premium version of Betternet. Selecting a specific server will assign you an IP address for that country, making it appear like you're browsing from that country.

To select a server, click on the country select button in the Betternet app. By default, this says Optimal.

This will take you to a list of available countries. Select the country you want to connect to.

After selecting a country, you will get connected to that country whenever you connect to Betternet.