구현 방법

ToolbarItem(placement: .navigationBarLeading){
  Button(action: {} ) {
    Image(systemName: "gearshape")
  }.accentColor(.red)
}

NavigationView {
  // 省略 //
}
.accentColor(.red)

구현 예

import SwiftUI

struct HomeView: View {

  var body: some View {
    NavigationView {
      Text("Hello")
      .navigationBarTitleDisplayMode(.inline)
      .navigationTitle("タイトル")
      .toolbar {
        ToolbarItem(placement: .navigationBarTrailing){
          Button(action: {} ) {
            Image(systemName: "gearshape")
          }
        }
      }
    }
    .accentColor(.red)

  }
}