Welcome to the Q&A Forum

My client has an old eCommerce website that is ranking high in Google. The website is not responsive for mobile devices. The client wants to create a responsive design mobile version of the website and put it on a different URL address. There would be a link on the current page pointing to the external mobile website. Is this approach ok or not? The reason why the client does not want to change the design of the current website is because he does not have the budget to do so and there are a lot of pages that would need to be moved to the new design. Any advice would be appreciated.

Lets say B  i a duplicate page of A (main page). I understand I have to put canonical tag under  B to point to A. Do I also put canonical tag under the main page A? Is it necessary? I understand that A would then tell Google that it is preferred page of A? Is this a correct understanding?