Avoid designing a form within your email for users to respond to. In plain text email, this looks cheap and suspicious.

Even with a graphics-enhanced email message, few people will actually fill it out. Instead, create your form on a separate web page (or as we email marketers call it: a "landing" page), and then add a hyperlink to that page within your email message.

Using an email marketing tool with an embedded update profile form will help you update and clean your customers' and prospects' data automatically.

Conclusion - Avoid designing a form within your email for users to respond to. Better add a hyperlink to a landing page with an update profile form or an automatic update profile form in your email tool.