To set breadcrumb, you have to install Yoast SEO plugin to be able to use the breadcrumb for website.
Download plugin: https://vi.wordpress.org/plugins/wordpress-seo/
Step 1: Go to WordPress Dashboard > SEO > Search Appearance
Step 2: Choose Breadcrumbs tab > Enable Breadcrumbs
Separator between breadcrumbs:
Step 2: Then "Save" the changes
Step 3: Go to WordPress Dashboard > Templates > Header
Step 4: You can drag 2 widgets Page Title and Breadcrumbs
After all, click "Update" for settings.