How to add a scroll function to a UILabel

Use UITextView (reference).

It's designed to do exactly that. Disable editing, and you get a scrollable label.

You can add your UILabel on a UIScrollView Like this and can also do like this---

scrollView.backgroundColor = [UIColor clearColor];

        UILabel * label = [[UILabel alloc] init];
        [label setNumberOfLines:0];
        label.text=[detailDict valueForKey:@"ABC"];
        [label setFont:[UIFont fontWithName:@"Georgia" size:16.0]];
        CGSize labelsize=[label.text sizeWithFont:label.font constrainedToSize:CGSizeMake(250, 1000.0) lineBreakMode:UILineBreakModeWordWrap];
        int y=0;
        label.frame=CGRectMake(38, y, 245, labelsize.height);
        [label setBackgroundColor:[UIColor clearColor]];
        [label setTextColor:[UIColor whiteColor]];
        scrollView.showsVerticalScrollIndicator = NO;
        y+=labelsize.height;
        [scrollView setContentSize:CGSizeMake(200,y+50)];
        [scrollView addSubview:label];
        [label release];

Here Y is used to increase or decrease the label size as the text.