Although the answer provided by @tolbard is amazing and works well!
I feel creating an extension for something that can be achieved in just a line of code, would be an over kill.
You can get bold as well italic styling for the same text in your label
by setting up the font property using UIFontDescriptor
as shown below in the example below using Swift 4.0:
label.font = UIFont(descriptor: UIFontDescriptor().withSymbolicTraits([.traitBold, .traitItalic])!, size: 12)
Other options include:
traitLooseLeading
traitTightLeading
traitUIOptimized
traitVertical
traitMonoSpace
traitCondensed
traitExpanded
For more information on what those symbolic traits mean? visit here