You first need to login to WHMCS to accomplish this task.
1. Hover on “Setup” on the menu tabs at the top, and select “General Settings”
2. If you are accessing “Setup” for the first time since you logged in, you might have to input your admin password for security purposes.
3. Select the “Localisation” tab.
The content will appear as below.
4. Go to the “Default Country” field and select the country you want to change to.
5. You can also choose to change the “Default Language”.
6. Save Changes.