Initialize the UITextField with a CGRect as a frame:
Swift
let textfield = UITextField(frame: CGRect(x: 0, y: 0, width: 200, height: 21))
Objective-C
UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(0, 0, 200, 21)];
You can also create a UITextField in Interface Builde...