JAVASCRIPT

material ui input placeholder color

const styles = {
  'input-label': {
    textOverflow: 'ellipsis',
    whiteSpace: 'nowrap',
    overflow: 'hidden',
    width: '100%',
    color: 'red'
  },

  'input': {
    '&::placeholder': {
      textOverflow: 'ellipsis !important',
      color: 'blue'
    }
  }
};

uitextfield change placeholder color

swift 5 
myTextfield.attributedPlaceholder =
NSAttributedString( 
  string: "placeholder text", 
  attributes: [
    NSAttributedString.Key.foregroundColor: UIColor.red
  ]
)