Annotable is the most full-featured all-in-one image annotation tool available for iPhone. It has been featured by Apple in several categories, including Best of 2016, New Apps We Love, Best Apps to Edit Your Photos, Best Productivity Apps, and Best Utilities. This app allows users to annotate images with various tools such as rectangles, ovals, arrows, lines, and texts. Users can fully customize their annotations with options for colors, sizes, outlines, and fonts.

Annotable also offers features to obscure private information with Blur and Pixelation, or highlight specific areas with Spotlights or a Loupe. One unique feature of Annotable is the ability to highlight text on screenshots of apps like Notes, Twitter, and Safari. This app supports Action Extension, Photo Editing Extension, Edits Sync via iCloud Photo Library, URL Schemes, 3D Touch, and Wide Color, making full use of the powerful iOS system.

Annotable stands out from other similar apps with its support for high-resolution images, not just screenshots. Additionally, it allows for direct annotation of large images without the need for cropping.