mj-button-example.mjml

<mjml>
  <mj-body>
    <mj-section>
      <mj-column>
        <mj-button font-family="Helvetica" background-color="#f45e43" color="white">
          Don't click me!
         </mj-button>
      </mj-column>
    </mj-section>
  </mj-body>
</mjml>