ComPDFKit PDF SDK requires non-ARC. If you wish to use ComPDFKit PDF SDK in a ARC project, just add the -fno-objc-arc compiler flag. To do this, go to the Build Phases tab in your target settings, open the Compile Sources group, and double-click and type -fno-objc-arc into the popover.
To use the ComPDFKit Objective-C Framework in your Swift project, you have to create a Swift Bridging Header file in that project. The best way is to create the .h file Manually.
First, add a header file to your project with the name: MyProjectName-Bridging-Header.h. This will be the single header file where you import any Objective C code you need your Swift code to have access.
Find Swift Compiler - Code Generation section in your project build settings. Add the path to your bridging header file next to Objective C Bridging Header from the project root folder. It should be MyProject/MyProject-Bridging-Header.h