How to access a viewmodel as a function argument?

Android Studio shows an error:

Unresolved reference: abc

I tried changing the view model name and how it is instantiated, e.g. val myViewModel5 by viewModels<MyViewModel>()

class simpleViewModel : ViewModel() {
    val abc = 1;
}

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val myViewModel by viewModels<simpleViewModel>()
        setContent {
            MyApplicationTheme {
                // A surface container using the 'background' color from the
                Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colorScheme.background
                ) {
                    app(ViewModelProvider(this).get(simpleViewModel::class.java))
                }
            }
        }
    }
}

@Composable
fun app(v: ViewModel) {
    Text(v.abc)
}

But it doesn't matter what I do, I can't use the member of the view model. Shoud I use a single functon for the whole app?

You specified the wrong type for v. It should be simpleViewModel instead of ViewModel.

The convention is to name all types with an uppercase first letter though:

class SimpleViewModel : ViewModel() {
    val abc = 1
}

Also, in your MainActivity you already have the view model instance myViewModel, so you don't need to jump through hoops with ViewModelProvider(this).get(simpleViewModel::class.java). Also, you shouldn't pass view model instances around, just pass what is needed:

MyApplicationTheme {
    // A surface container using the 'background' color from the
    Surface(
        modifier = Modifier.fillMaxSize(),
        color = MaterialTheme.colorScheme.background,
    ) {
        App(myViewModel.abc)
    }
}

By convention, composables also start with an uppercase letter:

@Composable
fun App(abc: Int) {
    Text("$abc")
}