Google on Monday announced the company has begun to notify more websites of the migration to mobile-first indexing, which means the search giant will predominantly rely on the mobile version of the content for indexing and ranking in search query results.

Crawling, indexing, and ranking systems have typically used the desktop version of a page’s content, but Google has begun to roll out mobile-first indexing for those who follow the best practices. Marketers will find the information in its platform called Search Console.

For those using separate URL for desktop and mobile, Google cautions marketers and webmasters to verify both versions of the site in Search Console, check URL links, and ensure that servers have enough capacity to handle potential increases in crawl rates, since both will be crawled.

For the mobile sites only, owners will see a significantly increase in crawl rates from the Smartphone Googlebot.

Google will show the mobile version of pages in Search results and Google cached pages, Fan Zhang, Google software engineer, wrote in a blog post.

Since the majority of users now access its search engine and other services via a mobile device, according to Google, Zhang explains that the index will primarily use the mobile version of a page’s content.

Google says it is not creating a separate mobile-first index, and will continue to use only one index. This means Googlebots will primarily crawl and index pages with the smartphone code, related to browsers like Mozilla, Chrome, Safari and other mobile browsers.

The best practices for dynamic serving and separate desktop and mobile URL are a little different. For example, the mobile site should contain the same content as the desktop site. So if the mobile site has less content, Google suggests updating it to bring it up data, including text, images and videos.

Users should make sure that the structured data is present on both versions of the site, and that URLs in the structured data on mobile versions are  updated to the mobile URLs, and should make the metadata visible on both versions of the site.