Hi,
Loco translate > Themes > XStore > add the language you need https://gyazo.com/fed3dee6ba549640ff5bebd06f5b4ccc Translate the necessary strings.
Do the same for the XStore core plugin (Loco translate > Plugins > XStore core).
Also, don’t forget to choose the site language in Settings > General.
Regards,
Hung PD