After examining the XStore Dark demo, I liked the functions in the top left menu “Language selection” and “Currency selection”. After the purchase it turned out that it was empty, I did not find such functions in the widgets. What to do, why the topic does not match its demo version?
If you attentively checked the Dark demo you saw that that select is just dummy select and not the real switcher http://prntscr.com/oitppj
If you want to implement the real language switcher use one of the additional plugins that allow you to create the multilanguage site:
If you decide to use WPML then to implement currency switcher install WooCommerce WPML and add the switcher widget to left top bar widget area. In case you choose one of the other 2 plugins then you may use Multi-currency for WooCommerce plugin https://wordpress.org/plugins/woo-multi-currency/ or similar.