How to redirect to Index from another controller?

You can use the overloads method RedirectToAction(string actionName, string controllerName);

Example:

RedirectToAction(nameof(HomeController.Index), "Home");

You can use the following code:

return RedirectToAction("Index", "Home");

See RedirectToAction

Use the overloads that take the controller name too...

return RedirectToAction("Index", "MyController");

and

@Html.ActionLink("Link Name","Index", "MyController", null, null)

try:

public ActionResult Index() {
    return RedirectToAction("actionName");
    // or
    return RedirectToAction("actionName", "controllerName");
    // or
    return RedirectToAction("actionName", "controllerName", new {/* routeValues, for example: */ id = 5 });
}

and in .cshtml view:

@Html.ActionLink("linkText","actionName")

OR:

@Html.ActionLink("linkText","actionName","controllerName")

OR:

@Html.ActionLink("linkText", "actionName", "controllerName", 
    new { /* routeValues forexample: id = 6 or leave blank or use null */ }, 
    new { /* htmlAttributes forexample: @class = "my-class" or leave blank or use null */ })

Notice using null in final expression is not recommended, and is better to use a blank new {} instead of null