Form with multiple steps (wizard style) in Flutter - Best approach

You can use the Stepper Widget. it can enable you from making vertical or horizontal wizard from multiple steps.

Stepper({
  Key key,
  @required this.steps,
  this.physics,
  this.type = StepperType.vertical,
  this.currentStep = 0,
  this.onStepTapped,
  this.onStepContinue,
  this.onStepCancel,
  this.controlsBuilder,
})

You can follow this example by Paul Halliday https://developer.school/flutter-how-to-use-the-stepper-widget/