Set Schema JSON-LD from Meta Option

First, you need to support Schema in your desire post type, See the documentation. Then in your single post type you will see Review & Schema Settings Meta Box.

You need to configure the settings look like the following screenshot.

  1. Schema Tab: First click on Schema tab to add custom Google Schema JSON
  2. Custom rich snippet? (Manual) : You must enable this option to set your custom Schema JSON Data it will override auto-generated settings.
  3. Rich snippet category: Which snippet category you want to show select from here.
    1. Article
    2. News Article
    3. Blog Posting
    4. Event
    5. Local Business
    6. FAQ
    7. Service
    8. Q & A
    9. How To
    10. About
    11. Contact
    12. Person
    13. Movie
    14. Audio
    15. Video
    16. Breadcrumb
    17. ItemLists
    18. Product – Woocommerce & EDD [Pro]
    19. Course [Pro]
    20. Job Posting [Pro]
    21. Recipe [Pro]
    22. Software App [Pro]
    23. Image License [Pro]
    24. Special Announcement [Pro]
  4. Category schema field: When you choose the Rich snippet category then the necessary meta field will be shown.

Note: You must fill up the required red * fields otherwise it will give a schema error.

Google Schema Validation Check: After fill up all necessary field check your page/post URL from here. Look like the following.