How can I increase the Tap Area for UIButton?

Very easy. Create a custom UIButton class. Then override pointInside... method and change the value as you want.

#import "CustomButton.h"

@implementation CustomButton

-(BOOL) pointInside:(CGPoint)point withEvent:(UIEvent *)event
{
    CGRect newArea = CGRectMake(self.bounds.origin.x - 10, self.bounds.origin.y - 10, self.bounds.size.width + 20, self.bounds.size.height + 20);
    
    return CGRectContainsPoint(newArea, point);
}
@end

It will take more 10 points touch area for every side.

And Swift 5 version:

class CustomButton: UIButton {
    override func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
        return bounds.insetBy(dx: -10, dy: -10).contains(point)
    }
}

You can simply adjust the content inset of the button to get your desired size. In code, it will look like this:

button.contentEdgeInsets = UIEdgeInsets(top: 12, left: 16, bottom: 12, right: 16)
//Or if you specifically want to adjust around the image, instead use button.imageEdgeInsets

In interface builder, it will look like this: