You have to use func setTitleColor(_ color: UIColor?, for state: UIControlState) the same way you set the actual title text. Docs
func setTitleColor(_ color: UIColor?, for state: UIControlState)
isbeauty.setTitleColor(UIColorFromRGB("F21B3F"), for: .normal)
Swift UI solution
Button(action: {}) { Text("Button") }.foregroundColor(Color(red: 1.0, green: 0.0, blue: 0.0))
Swift 3, Swift 4, Swift 5
to improve comments.This should work:
button.setTitleColor(.red, for: .normal)
Example in setting button title color
btnDone.setTitleColor(.black, for: .normal)