Once you have bought a domain name, bought hosting at WP Engine and installed WordPress, you can now start configuring your new website.
One of the very first things to consider is do you want to address your site with the www subdomain or without it.
Normally, I prefer to have www in my website URLs. But recently, simply because it is easier to do so, I have reverted to some of my sites using only the naked domain.
If I am running a WordPress multi-site I use a naked domain, and it I am running a straightforward, non-multi site, then I use the www in my URLs.
Why? Because it is easy to set up a www sub-domain on simple WordPress site, see my tutorial for achieving this on WP Engine, but harder to do it for multi-sites. If you’d like to add the www to a multi-site however, you can simply ask WP Engine support for help.