Email Autoresponder allows you to collect any number of custom fields on a subscription form. This information is stored with the subscriber's record and can be included in messages to that subscriber using the {CUSTOM_whatever <default>} tag (more on that later).
You can add custom fields to your subscription form in your web page editing software. Custom fields are not part of the automatic code generation process.
Any field on your form that contains custom_whatever will be captured by Email Autoresponder and stored in the subscriber's record.
For example, if you want to ask the subscriber to enter their fax number, you could create a form field called custom_faxnumber. An example HTML tag for this would be
<input type='text' name='custom_faxnumber'>
Note that Email Autoresponder only allows custom field information that fits on a single line so multi-line text area form fields cannot be used to gather custom field information into Email Autoresponder.