# Email Input Field Trigger
## 1. Add the HTML Form [#1-add-the-html-form]
Ensure your HTML form includes the `surface-form-handler` class. This class is essential for identifying the form as one that triggers the Surface Form popup. Example:
```html
```
Add the **`surface-form-handler`** class to any external form that you want to use to trigger the Surface Form popup.
## 2. Surface Form Constructor [#2-surface-form-constructor]
Add the following code to the **`pages/_document.tsx`** file:
```tsx
import Document, { Html, Head, Main, NextScript } from "next/document";
import Script from "next/script";
export default class MyDocument extends Document {
render() {
return (
);
}
}
```
Add the `data-question-id` attribute to your Surface Tag script in the **`pages/_document.tsx`** file.
You must replace the **``** within **`data-question-id`** attribute and **`REPLACE ME WITH FORM URL`** with the question ID from the Surface Form Builder and the form URL respectively.
