How to set UITextField height?

You can not change the height of the rounded rect border style. To set the height, just choose any border style other than rounded border in Xcode:

I finally found the fix for this!

As we have found, IB doesn't allow us to change the height of the rounded corner border style. So change it to any of the other styles and set the desired height. In the code change the border style back.

textField.borderStyle = UITextBorderStyleRoundedRect;

CGRect frameRect = textField.frame;
frameRect.size.height = 100; // <-- Specify the height you want here.
textField.frame = frameRect;

If you are using Auto Layout then you can do it on the Story board.

Add a height constraint to the text field, then change the height constraint constant to any desired value. Steps are shown below:

Step 1: Create a height constraint for the text field

Step 2: Select Height Constraint

Step 3: Change Height Constraint's constant value