A clear focus keyword without these stop words will reach out your audience. Also, search engines will know that you have some strong relevant content and gives importance to your site.
Use of Stop words in URLs : Take this URL as an example www.yoursite.com/category/this-is-how-not-how-to-have-a-url-structure/
List of common stop words
A, is, what, who, how, was, this, that, but, at, be, for, he, she, iam, I, in, its, your, with, all, any, did, do, had, has, here, his, and, etc.
2- Avoid using filter words to increase the effectiveness of your keywords.
3- Make sure that your web pages have the right keyword density and don’t contain stop words.
The right keyword mix on your web pages will help you to improve your ranking on all important search engines.