Page or Post Metabox contains three sections 1. Sidebar layout 2. Page Header and 3. Post Social
Hide Page Header(on MetaBox)
Enable Toggle Sidebar
You can hide/show toggle sidebar icon which is located on main menu. Path of this control: Customizer->Site Header Panel->Navigation Section->Enable Toggle Sidebar
If you click on toggle side icon sidebar will be opened on right side. You can insert one or more widgets on this bar.