Hi, im new with the WP
Welcome to WordPress. ??
I think you may be confusing themes with posts and pages.
Themes handle the presentation (look and feel) of your data. When you change a theme the look changes but when you have published a post or a page then it becomes visible to everyone else.
The word “publish” really applies to posts and pages. What it looks like you are talking about is making changes to your theme. Those changes get made as soon as you save the option.
What I was suggesting (badly) is that if you want to try out themes and different theme options that you do so on a separate install.
For example: on your live install (that the whole Internet sees) you might be using Twenty Thirteen. But you’d like to make changes using different options or even another theme.
That’s fine but if you make those changes elsewhere just write down what you’ve done on that separate installation. When you like what you’ve done then just manually make those same changes on your live WordPress installation.