Can I change the currency displayed by default on my store?

By default, the app will geolocate your visitors from the IP address and display the prices in their local currency.

For example, if the customers are from UK they will see GBP currency first. If the drop-down over the prices or the currency menu button is configured, they can use it to switch to other currencies.

However, you can disable geolocation and make the app convert by default to one particular currency. 

To do that you have to click on the Currency list and geolocation section from the app preferences dashboard page.

And then, look for the following option: "Default conversion currency" (USD is configured in the example below):
Please note that this will effectively disable geolocation and USD will be displayed for all customers unless they have selected a different currency in the drop-down list.