Declare and initialize the placeholder

@State private var specialInstructions = "Special Instructions"

Take it off once the user starts typing

TextEditor(text: $specialInstructions)
.foregroundStyle(.black) // Set your text color
.frame(height: 50) // Set the height you want for your field
.cornerRadius(8.0)
.onTapGesture(perform: {
if specialInstructions == "Special Instructions" {
    self.specialInstructions = ""
  }
})