This data shows your average users usage of mobile vs computer. Clearly mobile is the number one place for search.

Previously google ranked the desktop first and then would make allowances based on the mobile performance.

Rankings will continue to pull in data from desktop or app content if required, but the primary focus is on mobile. Desktop will be used if it has additional ranking information but there’s no guarantee that it will be crawled. 

The focus on mobile simply aims to provide an optimal search experience for users. This has been a transitory process to date but as of September 2020 all sites will be indexed mobile-first.

Don’t fret just yet. Google’s already confirmed that most sites are ready for this transition and they’ve actually shifted 70% of sites over to mobile first indexing already (after checking they’re ready). 

So this means that your site should be mobile responsive and to design for mobile first. Speed is critical as not everyone has good internet or a fast phone.

• You can test your site  by typing the URLs of both versions into the Structured Data Testing Tool and comparing the output.
• Have your developer remove any unnecessary markup that isn’t relevant to the content of each page. 
• Verify your mobile version is accessible to Googlebot using the robots.txt testing tool 
• Ensure you have verified your mobile site in Google Search Console 

This will lead to you establishing a solid simple site that is light and simple to load.