A class method is a method whose execution is scoped to the method’s class. It does not require an instance of an object to be the receiver of a message.

An instance method is a method whose execution is scoped to a particular instance of the class. In other words, before you call an instance method, you must first create an instance of the class. Instance methods are the most common type of method.

Complete Example:

#import< Foundation/Foundation.h>
 
@interface SampleClass:NSObject
    + (void)classMethod;
    - (void)instanceMethod;
@end
 
@implementation SampleClass
    +(void)classMethod{
        NSLog(@"This is a class method.");
    }
    -(void)instanceMethod{
        NSLog(@"This is a instance method.");
    }    
@end
 
int main()
{
    [SampleClass classMethod];   // calling class method
 
    SampleClass *object = [[SampleClass alloc]init];
    [object instanceMethod];      // calling instance method
 
    return 0;
}