I would like to collect information of my buyers from the newsletter I send to them and engage with them. eg, Was this newsletter helpful? what would you like to know more?
I'm not sure whether it will be a button they click through and bring them to a landing page with enquiry form, or is it possible for them to type their question in the newsletter and it comes to me?
You can't put the form field in the email itself.
You'll bring them to an LP with a form. The form need not include anything but the textarea and Submit button.