creating smart object

There are MANY programs in a full subscription, plus other non-subscription programs
Please post the exact name of the Adobe program you use so a Moderator may move this message to that forum

I'm not sure what you're really looking for (especially as you don't mention which Adobe app you're using). The mock up is not the web site, it's just a demonstration of what the web site would look like. After that, the design work begins. This design work is redone or modified for each change to the web site.

If the client provides text or pictures, you add them to the web design, and update the web design for them. If the client is contantly updating information beyond the point where editing the site is practical, they need a dynamically generated web site, which is a whole different thing.