Check out example codes for "flutter textfield label color". It will help you in understanding the concepts better.

Code Example 1

labelStyle: TextStyle(
	color: Colors.white,
)

Code Example 2

ThemeData( 
  // (...)
  hintStyle: TextStyle(
     color: Colors.grey, // <-- Change this
     fontSize: null,
     fontWeight: FontWeight.w400,
     fontStyle: FontStyle.normal,
     ),
);

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