@Ch0oJoy Так правильно:
<table cellspacing="0" cellpadding="0" style="font-family: Helvetica, Arial, sans-serif; font-size: 12px; font-weight: normal; margin-bottom: 10px; border-spacing: 0px; border-collapse: collapse; padding: 0px; vertical-align: middle;"><tbody><tr style="padding: 0; vertical-align: middle;">
<td class="button" align="center" style="padding: 8px 30px; -webkit-border-radius: 5px; -moz-border-radius: 5px; border-radius: 5px; color: #ffffff; display: block; word-break: break-word; -webkit-hyphens: auto; -moz-hyphens: auto; hyphens: auto; border-collapse: collapse!important; vertical-align: middle; font-family: "Helvetica","Arial",sans-serif; font-weight: normal; margin: 0; line-height: 23px; font-size: 14px; width: auto!important; text-align: center; background-color: #ef233c;">
<a class="btn_txt" href="https://my-site.com/index.php?route=account/order/info&order_id={order_id}" style="color: #ffffff; font-size: 16px; font-weight: bold; font-family: sans-serif; text-decoration: none; display: inline-block;">Мои заказы</a>
</td>
</tr></tbody></table>
где, вместо https://my-site.com подставить свой домен.