Change background color of TextEditor in SwiftUI

iOS 16

You should hide the default background to see your desired one:

TextEditor(text: .constant("Placeholder"))
    .scrollContentBackground(.hidden) // <- Hide it
    .background(.red) // To see this

iOS 15 and below

TextEditor is backed by UITextView. So you need to get rid of the UITextView‘s backgroundColor first and then you can set any View to the background.

struct ContentView: View {
    init() {
        UITextView.appearance().backgroundColor = .clear
    }

    var body: some View {
        List {
            TextEditor(text: .constant("Placeholder"))
                .background(.red)
        }
    }
}

Demo

_{You can find my simple trick for growing TextEditor here in this answer}