How do you create a sign up form using kirby

The CMS Questions
1

I want to create a sign up form that will send an email inregards to my latest offers and deals to whom ever signs up. Can I create a normal sign up form using php, html and css, if so how would i intergrate that into an exsisting website?

2

Yes.
create your form in your template and what you want to perform in the corresponding controller.
The controller must have the same name like your template than it will be loaded automatic.

3

You can use this or any of the other form examples as basis: Creating pages from frontend | Kirby CMS

Question is how you want to store your users and how you want to implement double-opt in which at least here in Europe is a legal requirement to be sending emails to users. That’s why using a newsletter service that takes care of such stuff automatically and is usually the better option to send bulk email anyway if you don’t have your own mail server.