What is the right way to add a form to my plugin?

When I search for information regarding creating a form for a plugin, all I get is a list of WordPress plugins. Is there not a standard way to do this?

I've been trying to create a form using a shortcode but the form displays above the header. I found some information on adding some surrounding code to make it load in the right place but it's not working.

public function load_shortcode()
{ 
    ob_start(); ?>

    <h1>Information</h1>
    <p>Fill out this form</p>
    <form>
        <input type="text" placeholder="Name">
        <input type="email" placeholder="Email">
        <textarea placeholder="Hello"></textarea>
    </form>

    <?php
        $output = ob_get_contents();
        ob_end_clean();
}

What is the right way to add a form to my plugin?

Thank you.