Read up on what a file system is on Wikipedia. Your iPhone already runs APFS, and you will never really have a need to 'utilize' it when you dont even know what a file system is.
Here's a good overview: https://www.imore.com/apfs
There's nothing to "utilize." There are no user-facing features that you'll notice on a day-to-day basis, except when you duplicate files, which should be instantaneous (See the article.) Eventually, it should give us some more powerful features in Time Machine.
Basically, APFS is just a more modern filesystem that is better suited for SSDs and is less prone to data loss. It's not something the average user should think or worry about.