For future readers, don’t have the same misunderstanding as was expressed above: we help Notepad++ users to use Notepad++. We are quite happy to do so. I personally tackle many Notepad++-related problems in this forum nearly every day. Just look at the recent posting history for factual proof of this.
What we cannot be is the entirety of stack exchange: we do not have experts on every possible programming language and every possible markup language and every possible cookie recipe.
Just because you use a particular text editor to type your source code doesn’t mean that the forum for that text editor should be expected to answer any programming questions you have.
If you have a C-programming question, go to a forum that specializes in C. If you have an HTML+CSS+JavaScript question, go to a forum about web authoring. If you have a question about cookie recipes, go to a cooking or baking forum. If you have questions about how to sort the text in your text file that you’re editing with Notepad++, this is the right place for you.
But going back to @Munawar-Ali’s question: it was said, “still it just shows the html on browser” – that might be interpreted as “it is showing the raw HTML markup rather than the rendered webpage”. If that’s the case, then you can use Notepad++ to save the file as HTML and give it a .html extension. And when you are using Notepad++ to type your HTML and CSS files, you can have your saved HTML file in the active tab in Notepad++ and run View > View Current File in… to pick your favorite browser, and Notepad++ will issue the command for that browser to open the active file in the browser; if it’s properly saved as HTML, and the browser will render that HTML file as a local webpage; if the HTML is written correctly (with all the files in the right place relative to each other), then it will render correctly in the chosen browser.