account.html

<!-- app/code/Simmi/Theme/view/frontend/web/template/account.html -->
<div data-bind="text: loadingText"></div>

account.js

// app/code/Simmi/Theme/view/frontend/web/js/account.js
define([
    "uiComponent",
    "jquery",
    "ko",
    "underscore",
    "mage/translate",
], function(Component, $, ko, _, $t) {
    return Component.extend({
        defaults: {
            template: 'Simmi_Theme/account.html',
            loadingText: $t('Please wait...'),
        },
        initialize: function() {
            var self = this;
            self._super();
            // any other init code here
        }
    });
});

account.phtml

<!-- app/code/Simmi/Theme/view/frontend/templates/account.phtml -->
<div data-bind="scope: 'accountOverlay'" id="account-overlay">
    <!-- ko template: getTemplate() --><!-- /ko -->
</div>

<script type="text/x-magento-init">
    {
        "*": {
            "Magento_Ui/js/core/app": {
                "components": {
                    "accountOverlay": {
                        "component": "Simmi_Theme/js/account"
                    }
                }
            }
        }
    }
</script>