Google's new (and now properly branded) security system, Google Play Protect, is now widely available and should at this point be active on any phone with the latest version of Google Play Services. After a slow rollout with varied reports that Play Protect was available, as we look at our own devices here every one of them has it.
Google announced Play Protect back at Google I/O as a revamped and more consumer-friendly version of the old "verify apps" system, but with an identical goal: to protect you from harmful apps installed on your phone. Functionally, things aren't much different today than they were in the old verify apps world, meaning Google is constantly tracking apps to make sure they're all on the up and up, no matter what phone you have. But the aim of Play Protect is to let the user know what's going on with the scanning in a way that wasn't really available before.
You can find Play Protect by going into your Google settings, then Security and Google Play Protect. The interface is simple, and lets you know how many apps were recently scanned, when the scan occurred and how everything looks. A big green check mark will greet you if everything looks good. Eventually, this confirmation will be surfaced in the Play Store as well.
If your phone doesn't yet have Play Protect, don't think that your phone is left insecure — but once it does, it's worth poking around in the (admittedly simple) settings to see what it's all about. But the most important thing you can do is just keep that "scan device for security threats" toggle turned on. Google can't catch every malicious app, but it has historically done a pretty great job and now users have a better feeling for what's happening with app security on their devices.