You access the tools from along the bottom of the screen. Fix offers cropping and rotating; exposure adjustments; freehand and face-specific warping; healing, cloning and redeye reduction; smoothing and sharpening; lighten, darken and clarity (called "structure"); saturation, desaturation and "pop"; painting; selective blurring; and vignetting.
You can open an image from your iPad's photos, use the camera, open an image from Creative Cloud or a Lightroom synced collection, grab one from Facebook, or download from Dropbox.
Here you can see the paint-on masks of the darkened (red) and lightened (green) areas. You can control the brush size, edge hardness and transparency. In the upper left corner, the leftmost icon brings up a layer opacity slider; the tool next to it is a before/after toggle.
One of Fix's notable tricks is simplified facial-structure retouching. It automatically detects the eyes, cheeks, nose, mouth and chin and brings up warping tools specifically designed to alter the basic characteristics of each.
I was pleasantly surprised at the addition of a CMYK color picker to Fix, which I believe is the first Adobe mobile app to include one. You can also choose from among preset color themes and custom themes from Adobe Color CC and Adobe Hue CC that are stored in your libraries.
Global exposure adjustments include brightness and contrast, color saturation and shadow and highlights. One glaring omission is white balance.
I really hate that the sliders have no units and there's no histogram display, since screen preview isn't reliable enough and if you want to use the same settings again you have to remember stuff like "shadows three units up." On the other hand, the slider display mimics a distribution curve, with large increments in the middle getting smaller as you get to the tails. The app doesn't seem to have any algorithms in place to safeguard the integrity of the tonal curve, though, to prevent odd results (like getting gray areas if you push highlights all the way down and shadows all the way up).
Options here include spot healing, cloning and red-eye reduction. Spot healing automatically overlays and blends in another section of the image to cover spots, while patch lets you select the section used for the overlay. You clone by tapping a source location and then painting over the target area; you can't move the source location once you've painted with it. I couldn't test red-eye because I can never find any shots with it.
When you send a edited photo to the desktop, it comes into Photoshop as a file with adjustment and mask layers for many operations. Some other operations, such as warping, get rasterized into the photo. While this is really useful, I was kind of hoping it would perform a little more intelligently, such as mapping vignettes to Photoshop vignettes so they'd be re-editable, instead of a clunkier-to-refine mask.
When editing photos and sending them directly to Photoshop, gaps and spikes appear in the histogram. That indicates clipped color values. On the other hand, when I sent the identical image back to Lightroom then opened it in Photoshop, it didn't have the same problem. However, then you lose the mask editability.
Once you're done, you have a handful of choices of what to do with your final project. Saving to library uploads it to CC and adds it to your My Graphics library; you can open it normally from there. Sending to Photoshop converts it to a PSD file, uploads it, launches all copies of Photoshop that are logged into the relevant account (which is really irritating) and loads the file. If you save to Lightroom, it syncs the file back to the original (if it was originally from Lightroom) or creates a copy in a new synced collection. Other options are saving it to your Camera Roll; publishing it as a Behance work-in-progress; directly sharing to Facebook or Instagram; or uploading to any service supported by your iPad's share sheet.