Add Background Color to Tables in Email Signatures

Short answer:
Use the bgcolor attribute to apply background colors to tables or table cells in HTML email signatures.

You can apply a background color directly to a full table:

<table bgcolor="#00FF00">
  ...
</table>
	

Or apply a background color to a specific table cell (td):

...
<td bgcolor="#00FF00">Row</td>
...
	

This approach is widely supported in email clients and is recommended when designing HTML email signatures.