The strong front lighting reduces shadows, for example on her face, that normally provide visual clues about the depth of her features (e.g. how large her nose is) this tends to flatten a persons features to a degree as pointed out by rangibaby.
The overall focus in strongly divided into foreground features and very blurred background features. I haven't played around with the ability of the iPhone 7+ to do this blurring algorithmically, but it is very commonly done with SRL cameras by choosing a very shallow depth of field. This is done by using a large aperture, say f2 or f2.8. This wider open lens allows more of the outer, more curved, part of the lens to collect and focus light onto the image, and due to the geometry of the optics this makes the range of the scene that remains in sharp focus much shallower. (See, https://en.wikipedia.org/wiki/Depth_of_field .) Notice particularly, the excellent bokeh formed by the blurred lights in the background. (https://en.wikipedia.org/wiki/Bokeh)
Finally, a flash combined with a wide open lens can overpower the exposure, a problem for film's limited range of sensitivity (film speed). Cameras can compensate for this by using insanely short exposures, like 1/8000 second, and/or adjusting the exposure sensitivity for a few individual shots (film cameras require changing film rolls to change sensitivity, but today's digital cameras can automatically change the sensitivity on a per shot basis). To me, the picture has a frozen, surreal aspect that can come from a high shutter speed.
All of these effects, which can be done with the appropriate camera settings, can also be simulated with enough Photoshop work. This particular photo could have just been produced serendipitously, especially in this age of unlimited snaps from cell phones that never run out of film, but it looks more professional to me. Consider the careful edge lighting that separates the hair from the background. (See https://www.slrlounge.com/5-ways-to-separate-your-subject-fr... )