Transfer website to another website

Hi, I have been working on a website for a client, and now they want the website on another website inside Squarespace, there's a way that I can transfer this website to the other one that is already created? I'm not sure if this can be done. If is not, let me know, thanks

If you are asking if you can copy pages from one site to another, that is possible for the most part, this chrome extension has been used by many but not having used it myself I  don't know how well it works.

https://www.squarewebsites.org/squarespacewebsites-tools-extension-pro

 If you want to link the two sites using one domain as the lead domain, then pick the site with that domain and add a landing page to that site with buttons or other links that direct to both sites.