wp-calypso/packages/components/src/icons/mail.tsx

import { SVG, Path } from '@wordpress/primitives';

// TODO: replace with an icon when available.
const mail = (
	<SVG xmlns="http://www.w3.org/2000/svg" viewBox="0 0 32 32">
		<Path
			fillRule="evenodd"
			clipRule="evenodd"
			d="M4 9.33329C4 7.86053 5.19391 6.66663 6.66667 6.66663H25.3333C26.8061 6.66663 28 7.86053 28 9.33329V22.6666C28 24.1394 26.8061 25.3333 25.3333 25.3333H6.66667C5.19391 25.3333 4 24.1394 4 22.6666V9.33329ZM6.66667 8.66663H25.3333C25.7015 8.66663 26 8.9651 26 9.33329V10.5833L16.0001 18.0833L6 10.5832V9.33329C6 8.9651 6.29848 8.66663 6.66667 8.66663ZM6 13.0832V22.6666C6 23.0348 6.29848 23.3333 6.66667 23.3333H25.3333C25.7015 23.3333 26 23.0348 26 22.6666V13.0833L16.0001 20.5833L6 13.0832Z"
		/>
	</SVG>
);

export default mail;