Put something like this in your form:
<textarea id="comments" name="comments"
rows="5" cols="33">
Please add any comments here.
</textarea>
You will have to parse for this information in your server side code. It depends if the cart.asp page supports extra form field procession.
BTW, .asp is really old tech! I used to use it .... about 250 years ago!
If you run into issues just contact me. Occasionally things come up, most of the time is people just dealing with learning to code ... they soon figure out what they missed. Once in a while, there are actual errors though.
Good question. Learn the basics and these things will become obvious to you:
https://school.studioweb.com/store/course/complete_web_designer
You will learn to build your first web page in about 40 minutes.
I hope that helps!
Have you done my basic HTML and CSS course? If you have, this would be pretty easy. That said, you have to learn about linking and paths.
https://school.studioweb.com/store/course/complete_web_designer
Stef