Objective-c code Apple style documentation set generator
appledoc is command line tool that helps Objective-C developers generate Apple-like sourcecode documentation from specially formatted sourcecode comments. It's designed to take as readable sourcecode comments as possible for the input and use comments as well as surrounding sourcecode to generate visually appealing documentation in the form of HTML as well as fully indexed and browsable Xcode documentation set. Additionally, you can of course use documentation generated by appledoc for your products (free or commercial), but you must attribute appledoc either in the documentation itself or another appropriate place such as your website.
Xcode plug-in which helps you write documentation comment easier
VVDocumenter-Xcode is an Xcode plugin that helps developers write documentation comments quickly and consistently in Objective-C and Swift. It automatically generates Javadoc-style comment blocks for methods, functions, and properties, improving code readability and API maintainability. It was especially popular before Apple introduced native documentation features in newer Xcode versions.