Do you already have a website?
How good is it?
Is your website mobile friendly?
Google recently changed their rules so that sites that are not mobile-friendly, they will appear lower down the search results in some situations.
Note Your site may pass this test and still not be optimal. The old way to make a website mobile-friendly was to show an alternative stripped-down version of the site to the visitor. Visitors hate this, and so the modern approach is to make the site automatically change and adapt to the screen.