To change the background color of a button in iOS application we need to access the property ‘ backgroundColor’ of the UIButton. We can do this in two ways, programmatically and using the storyboard.
Add a button on your storyboard, select it Go to it’s attribute inspector and select 'Background' property to choose the color.
Create outlet of the button on the View Controller.
In the viewDidLoad() or viewWillLayoutSubview() method add the code to change the background color.
btn.backgroundColor = #colorLiteral(red: 0.4392156899, green: 0.01176470611, blue: 0.1921568662, alpha: 1)
When we run the method one by selecting a color on the attribute inspector, below is the result that’s created.