Hide Page From Menu

I’m new at WordPress and I have a question. Can a newel created page be hidden – not assigned – to the main menu attributes and still be seen by others if coming off a link embedded in another page?

For example, I have a testimonials page assigned to the ‘About’ page attributes. I would like to create another page called ‘testimonial submission form’, where I link to that newel created page from the testimonials page.

I noticed when I create a testimonial submission form page, and I do not assign that page to a menu attribute, that page becomes part of my top menu structure. And or, if I assign that page to the ‘About’ attribute, it just creates another drop-down menu item, something that I’m trying to avoid.

Thanks in advance,
Mike