Below you can find an example of an email template (mobile responsive) with a header, a body and a footer. The header and footer content are centered. You can copy and paste this code into the editor (text mode). When you switch to visual mode, you can adjust the content and insert a logo, for example.
<table border="0" cellpadding="0" cellspacing="0" height="100%" width="100%" id="bodyTable">
<tr>
<td align="center" valign="top">
<table border="0" cellpadding="0" cellspacing="0" width="600" id="emailContainer">
<tr>
<td align="center" valign="top">
<table border="0" cellpadding="20" cellspacing="0" width="100%" id="emailHeader" style="background: #0073aa; color: #ffffff; font-size: 1.2em;">
<tr>
<td style="text-align: center;">
This is where my header content goes.
</td>
</tr>
</table>
</td>
</tr>
<tr>
<td align="center" valign="top">
<table border="0" cellpadding="20" cellspacing="0" width="100%" id="emailBody" style="background: #f9f9f9; color: #555555;">
<tr>
<td>
This is where my body content goes.
</td>
</tr>
</table>
</td>
</tr>
<tr>
<td align="center" valign="top">
<table border="0" cellpadding="20" cellspacing="0" width="100%" id="emailFooter" style="background: #f1f1f1; color: #555555; font-size: 0.8em;">
<tr>
<td style="text-align: center;">
This is where my footer content goes.
</td>
</tr>
</table>
</td>
</tr>
</table>
</td>
</tr>
</table>
This template is based on a Mailchimp (example) template which you can find here.
You can use the filter mentioned above if you want to use a custom <head> element or if you want to add code that is not possible through the editor.
If you have any more questions, feel free to ask. We are glad to help you.
Kind regards,
Team Download After Email