Button with Label and Alert

You need to actually toggle the showAlert state.

Code:

struct ContentView: View {
    @State private var showAlert = false

    var body: some View {
        Button {
            showAlert.toggle()
        } label: {
            Image(systemName: "info.circle")
        }
        .alert(isPresented: $showAlert) {
            Alert(title: Text("Impressum"), message: Text("?"), dismissButton: .default(Text("Okay")))
        }
    }
}

Result: