You can enable a site preloader, which is a subtle animation that loads on every page before a user can view your site. This can be turned on by navigating the following steps from your Shopify dashboard:
Online Store → Themes → Customise
Theme settings → Animation
This animation effect will not show when you are customising your theme in the . We want you to be able to change and update your site without having to wait for the preloader to finish loading.
When this setting is checked, customers browsing your live site however, will see the loading screen when browsing your store.