Why not using super method?

In previous chapters when we’re dealing with init, we use something like this:

- (instancetype)initWithabc
{
   self = [super init]
  ......

}

but I notice that either in the description or in this chapter, we are not using super method

description:

- (NSString *)description{
  NSString *descriptionString = [[NSString alloc] initWithFormat:<blablabla>];
}

in this chapter:

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    NSLog(@"%@ was touched", self);
    float red = (arc4random() % 100) / 100.0;
    float green = (arc4random() % 100) / 100.0;
    float blue = (arc4random() % 100) / 100.0;
    
    UIColor *randomColor = [UIColor colorWithRed:red
                                           green:green
                                            blue:blue
                                           alpha:1.0];
    self.circleColor = randomColor;
}

So when do we need to use super and when not??
Well to be more frank, how exactly the super works???