Mobile-first indexing is the method that Google has used to index sites as well as rank them, mainly using their mobile version of the content. As the world’s population continues to swell with users who access the internet through mobile devices, the focus of the whole search engine is on user-friendly mobile sites. Sites that have not been optimised for viewing on mobile devices will be losing out substantially in the rankings on search engines. Mobile-first indexing is all about offering a mobile experience that is just responsive and easy to use. Indexing and ranking websites by using their mobile version content is exactly what Google has done with mobile-first indexing. Numbers continuing to increase of their use of mobile devices to access the Internet have resulted to search engines like Google, no longer depending for indexing on desktop websites only but also on mobile-aware websites. Any site not optimised for mobile viewing loses some points on search engines, automated traffic acquisition, accumulations of data, and so forth. Mobile-first indexing strongly indicates that responsive mobile experiences and user-friendliness are a must-have.