Hi,
The tutorial will help you to set underline textfield in Xcode.

 #import <UIKit/UIKit.h>

    @interface UnderlinedTextField : UITextField

    @end

#import "UnderlinedTextField.h"

@implementation UnderlinedTextField

// Only override drawRect: if you perform custom drawing
// An empty implementation adversely affects performance during animation.
-(void)drawRect:(CGRect)rect {
    // Drawing code

CALayer *bottomBorder = [CALayer layer];
bottomBorder.frame = CGRectMake(0.0f, self.frame.size.height - 1, self.frame.size.width, 1.0f);
bottomBorder.backgroundColor = [UIColor lightGrayColor].CGColor;
[self.layer addSublayer:bottomBorder];

}
@end

Just add this category to your xcode project and select the textfield and go to the IB and give the name UnderlinedTextField to your textfield class and use it.