You can change your default currency between any of the fiat currencies available in your country of residence. On your device, log into your account. If you're not sure how to do this, go to the following article.
Once logged in, click the menu icon (≡) in the top right corner, then select “Setting”, and choose “Default Currency”.
You’ll be presented with a dropdown list of other available currencies. Select your preferred currency from the drop-down menu to change your default currency (i.e., GBP, USD, EUR, etc.).