What is Breadcrumb Navigation
Breadcrumb Navigation is a user interface which shows the current page location.
Where Breadcrumb Navigation Links appear in theme
Breadcrumb Navigation should appear just below page title as shown in below image.
How To Show Breadcrumb navigation
Home Administration Structure Block layout
Place Breadcrumbs block in Page Header region.
How To Hide Breadcrumb navigation
To hide Breadcrumbs, put it in Hidden blocks region or disable this block.