<!DOCTYPE html>

<html>

<head>

    <title>Form Example</title>

</head>

<body>

    <h1>Contact Form</h1>


    <form action="process.php" method="POST">

        <label for="name">Name:</label>

        <input type="text" id="name" name="name" required>


        <label for="email">Email:</label>

        <input type="email" id="email" name="email" required>


        <label for="message">Message:</label>

        <textarea id="message" name="message" rows="5" required></textarea>


        <input type="submit" value="Submit">

    </form>

</body>

</html>

Let's go through each part step by step:

1. `<!DOCTYPE html>`: This is the document type declaration and specifies that the HTML version used is HTML5.

2. `<html>`: This is the root element of the HTML document. All other elements are contained within it.

3. `<head>`: This element contains meta-information about the document, such as the title displayed in the browser's title bar.

4. `<title>`: This element sets the title of the HTML document, which is displayed in the browser's title bar or tab.

5. `<body>`: This element contains the visible content of the webpage.

6. `<h1>Contact Form</h1>`: This is a heading element that displays the text "Contact Form" as the main heading of the form.

7. `<form action="process.php" method="POST">`: This element defines a form. The `action` attribute specifies the URL or file where the form data will be submitted. In this example, it's set to "process.php". The `method` attribute specifies the HTTP method to be used when submitting the form, which is "POST" in this case.

8. `<label for="name">Name:</label>`: This is a label element that associates text with a form field. The `for` attribute specifies the ID of the form field it is associated with.

9. `<input type="text" id="name" name="name" required>`: This input element creates a text input field. The `type` attribute is set to "text" to indicate a single-line text input. The `id` attribute is used to uniquely identify the input field, and the `name` attribute specifies the name of the field that will be used when the form is submitted. The `required` attribute makes this field mandatory, meaning the user must fill it out before submitting the form.

10. `<label for="email">Email:</label>` and `<input type="email" id="email" name="email" required>`: These elements create a label and an email input field, similar to the previous "Name" field. The `type` attribute is set to "email" to ensure that the user enters a valid email address.

11. `<label for="message">Message:</label>` and `<textarea id="message" name="message" rows="5" required></textarea>`: These elements create a label and a textarea field for the user to enter a message. The `textarea` element allows multiple lines of text. The `rows` attribute specifies the number of visible rows for the textarea. Like the other fields, it is also required.

12. `<input type="submit" value="Submit">`: This input element creates a submit button. The `type` attribute is set to "submit". When clicked, it triggers the form submission process. The text "Submit" is displayed on the button.

In summary, the HTML code creates a basic contact form with fields for name, email, and message. The form data is sent to a server-side script called "process.php" using the HTTP POST method. The required attributes ensure that the user must fill out the mandatory fields before submitting the form.