Hi @Szeto, Sam ,
In this case will need to manipulate the DOM for your requirements. B2C injects the html inside the predefined div with id
set to api
(<div id="api>) as described here. You will need to check the structure of the html elements in the developer tools and then select the element using JavaScript to manipulate the DOM. You can use jQuery and select the elements like in this example where the user selects the Email Address label and removes it, and also replaces the "Sign in with your email address" text:
$("label[for='email']").remove();
$("#localAccountForm .intro h2").text("your custom text");