Google Mobile-Friendly Test is the yes/no answer to the question “How do I know if my website is mobile friendly?”. Since Google made mobile friendliness an important ranking signal, you should care about this question.

To cite Goole, there are 3 top things you should look after when building a website:

1. Make mobile experience easy for customers
2. Measure the effectiveness of your website by how easily mobile customers can complete common tasks
3. Select a mobile template, theme, or design that’s consistent for all devices (use responsive web design)

You can also use Google’s PageSpeed Insights to know how well your website performs in terms of loading speed both on PCs and mobile devices. This Google speed test will not only show you the speed, but also provide detailed instractions on how to fix problems and make thewebsite PC and mobile friendly.