This setting allows you to place your store in 'Maintenance Mode' and display a message to your shop's visitors when you may be doing some maintenance on your shop front and do not wish your customers to see the work in progress. To enable this mode, go to your Dashboard > Settings > My Account.
Tick the 'Enable storefront 'Maintenance Mode'.
Now if you select 'View Shop', you will get the below message. You can edit the message you wish to display by editing the 'maintenance.liquid'. If you are unsure how to do this, please contact support and we will be able to help.
Once your shop is in 'Maintenance Mode', you will be able to make the edits you require in your Shop Editor. When you have completed the work on your shop front, simply go back to My Account and untick the Maintenance Mode option.