Hello,
Thanks for using XStore and for contacting our support team.
1/ It works in the same way even with the default WC theme – Storefront, this functionality is independent of our theme and comes from the WooCommerce plugin, so if you want to change this, contact the support of WC.
2/ Registration functionality comes from WooCommerce plugin – https://woocommerce.com/document/configuring-woocommerce-settings/#accounts-and-privacy-settings
We do not have additional settings for this (just FaceBook / Google login can be activated – https://xstore.helpscoutdocs.com/article/87-facebook-login ), so we would recommend you to contact the support of WooCommerce.
Regards