How to set redirect url in Magento 2?

In Magento 2, You can redirect to any link or forcefully redirect to any link by Magento\Framework\Controller\Result\RedirectFactory object.

Using setUrl($url) -> You need to pass link as parameter for redirect
Using setPath($path) -> You need to pass path(action URL) as parameter

public function __construct(
    \Magento\Framework\Controller\Result\RedirectFactory $resultRedirectFactory
) {
    $this->resultRedirectFactory = $resultRedirectFactory;
}

1. Using a direct path, you need to pass the action URL in a setPath() method.

Redirect to the cart page,  Pass action path as checkout/cart,
Redirect to contact page, the parameter is `contact ` only
To Redirect to a login page, a parameter is customer/account/login

$resultRedirect = $this->resultRedirectFactory->create();
$resultRedirect->setPath('checkout/cart');
return $resultRedirect;

2. Pass Query string, Add Second Argument as a Query string array to use custom query string in URL.

$argument = ['id' => $getId, '_current' => true];
$resultRedirect = $this->resultRedirectFactory->create();
$resultRedirect->setPath('checkout/cart',$argument);
return $resultRedirect;

You can redirect to any link by direct URL using below way,

3. Full URL redirect with Magento,

$resultRedirect = $this->resultRedirectFactory->create();
$url = 'http://127.0.0.1/magento2/checkout/cart';
$resultRedirect->setUrl($url);
return $resultRedirect;

You need to pass the full URL for a redirect to a specific link in Magento 2 in the setUrl method.