Uplift provides support for displaying a currency switcher in the header aux items, when used in combination with WooCommerce + WPML.

In order to configure the plugins to add the currencies, you will need to follow this guide: https://wpml.org/documentation/related-projects/woocommerce-multilingual/multi-currency-support-woocommerce/

Once you have set that up, you can then add the Currency Switcher aux item to either the header left or right aux areas, in Theme Options > Header Options.