Hello,
1) Registration is the WooCommerce default option – https://docs.woocommerce.com/document/configuring-woocommerce-settings/#accounts-and-privacy-settings and it does not have settings to add additional fields by default. So, look for third-party plugins that allow you to customize WooCommerce registration, for example https://woocommerce.com/products/custom-user-registration-fields-for-woocommerce/ or https://wordpress.org/plugins/custom-registration-form-builder-with-submission-manager/ or similar that suits your needs.
2) For mobile only?
Regards















