Is it possible for me to create user-friendly demos for my clients?

Is it possible for me to create user-friendly demo websites for my clients that they can access and update certain fields with their own custom text and images to see before committing/purchasing? 

Hi,
If you haven't received an answer yet, you can post on some FB groups
+ Squarespace Customization Resource Groups
+ Squarespace Community
+ Squarespace Entrepreneur
+ Squarespace Rockstars