address payable to address conversion

address.sol

// SPDX-License-Identifier: GPL-3.0

pragma solidity ^0.7.0;

contract HelloWorldContract {

        function transferFund(address payable receiver, uint amount) payable external {

                address newAddress = receiver;
                receiver.transfer(amount); // OK
                newAddress.transfer(amount); // shows an error

        }
}