Making A New Page Without Changing The Page

Question

I basically want to make it so that if you press a button, it will change the features of the page to a different section of the code but doesn’t switch web pages.

Answer 1

What you need is a Single Page Application.

Traditionally SPA was developed using only ajax.
But now there are good JavaScript libraries like React js for developing Single Page Application.

Answer 2

If you mean something like a onepager you can jump to other areas of your website by using <a> tags like this: <a href="#id_of_some_element_on_your_page">Link</a>
If you would like to change your page content without reloading it you have to use AJAX.