You can get guest and customer other information in your custom js like customerinfo.js in Magento_Checkout/js/model/quote: define( [ 'jquery', 'Magento_Checkout/js/view/payment/default', 'Magento_Checkout/js/model/quote', 'Magento_Checkout/js/action/place-order', ], function ($,Component,quote,placeOrderAction) { 'use strict'; return Component.extend({ defaults: { template: 'Company_Module/custompayment/form_template' }, getEmail: function () { if(quote.guestEmail) return quote.guestEmail; else return window.checkoutConfig.customerData.email; }, getLastName: function () {...