The importance of optimizing your site for mobile use and mobile search could hardly be overstated. Mobile has become the “900 pound gorilla” of search. Most people do their searching on mobile devices and the percentage of people searching on mobile first is increasing every day.
A good first step in seeing where your site is at in this important area is testing your site mobile friendliness using a tool like this one: https://www.google.com/webmasters/tools/mobile-friendly/.
Knowing how your site appears can be really important because Google now has a separate search engine just for mobile sites, and if your site doesn’t test well for mobile, it will not rank well on Google’s mobile search engine.
If your site does not test as “mobile friendly” you can redesign it using what is called “responsive design” or you can design an entirely separate mobile site.
“Responsive Design” functionally means that no matter what device your site appears on, it will appear in a way that is perfect for the screen size it is being viewed on.
A “Mobile Only” version of your website is exactly what it sounds like, a separate version of your website designed only for being viewed on mobile devices.
Both types of mobile websites are good as long as from mobile user point of view, they are easy to navigate from their mobile devices.