Display error message on the view from controller asp.net mvc 5

But I read somewhere that I should put one property in my view model
and set the error message on that property. I am confused now, how to
achieve that and how to display the error in View then? And which one
is the recommended/best practice?

The best practice is to alter the ModelState dictionary property of your controller like this:

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Search(ForgotPasswordMV viewModel)
{
    // ... 
    else
    {
        ModelState.AddModelError(nameof(ForgotPasswordMV.Email), "Email not found or matched");
        return View(viewModel);
    }
}

Then in your view add the line below next to your email field;

@Html.ValidationMessageFor(m => m.Email)