playwright/packages/create-playwright/assets/examples/server/assets/file-uploads.html

<iframe src="header.html" style="width: 100%; height: 200px; border: 0;"></iframe>

<form action="/api/v1/file-upload" method="POST" encType="multipart/form-data">
    <input type="file" name="my-file"/>
    <input type="submit"/>
</form>