How to make my Wix website responsive in order to fit to any screen sizes?

I’m not a developer, so I don’t know how to use developer mode to add this feature on my website. Is it possible for me to do this or should I hire someone?

You are better suited going through Wix Support for your post question.
https://support.wix.com/en/article/contacting-wix-support

Or read the Wix Support pages about it.
https://support.wix.com/en/article/request-responsive-sites
https://support.wix.com/en/article/aligning-your-site-to-display-correctly-on-different-browsers

Or read previous posts.
https://www.wix.com/corvid/forum/community-discussion/responsive-site-layout