Content block — is specific layout of content that will be saved, then you will be able to reuse it to display in Page Title area, Top Bar area, Top Drawer or Footer area (configure in Theme Options or Preset, and only Page Title area in Page Options). By using Content Block you will be able to save tons of time in case you need to create specific layout on and apply it to be Top Bar/Top Drawer or Page Title/Footer.
You can consult our video guide on How to use Content Block in April theme for more details (In this video we used Emo theme for example and it is similar to April Theme)>
The screenshot below is all content block in April demo data. You can manage all your content block here by edit/delete/view.
Top Drawer Option
Top Bar Option
Page Title Option
Footer Option