To import a library in Objective-C, you use the #import directive. You can import both Apple frameworks and third-party libraries. Here are some examples:
#import // Importing the Foundation framework
#import "MyCustomLib.h" // Importing a custom library called MyCustomLib
#import // Importing a third-party library called AFNetworking
When you import a library, you can then make use of its classes, functions, and other components within your Objective-C code.