In March 2018, Google announced a change to their algorithms with the snappy title of Mobile-First Indexing. What does this mean? Do you need to do anything?
This means Google will now index your website based on its mobile version first, rather than desktop. This is because Google says more searches are now done via a mobile device than a desktop, so mobile should be the first priority.
A mobile website needs a different layout to a desktop website, because a mobile screen is small, often portrait-oriented, and is accessed via a touch-screen. Most desktop screens are large, landscape-oriented, and operated using a mouse. You may want the same content to display, but by necessity it has to be laid out differently. Things like the menu need to be totally different.
In around 2011-2012, responsive design arrived. A responsive website is one which resizes automatically according to the device it is viewed on. If your website is responsive, this algorithm change shouldn't impact your site (and happily, all WebSolutionZ-developed websites since 2012 have been developed using fully responsive templates). But if you want to make sure, Google provides a Mobile Friendly Test page so you can test your website.
If your website doesn't pass this test, it may mean a drop in rankings with Google.
With "mobile-first" in mind, it's really important to ensure your site doesn't just pass the Google Mobile Friendly Test, but is as usable as possible. UX, or "user experience", is also a ranking factor, so ensuring your site is mobile UX-friendly gives you a better chance of ranking well on search engines. This means things like enough space between elements so people don't accidently "click" the wrong thing, large enough fonts so the content can be read, and web-friendly content that doesn't require an hour of scrolling on a small screen.
Remember - even if mobile is not currently where the majority of your audience are - in 2018, mobile-friendly sites are indexed higher. If your website is not mobile-first, and your competitors are - guess what? ????