Where to put schema.org tags in HTML page?

Question

Where should I put schema.org tags? I have 3 options:

1. at detail page of article
2. at category page where are articles of category
3. at search page

Should I put schema.org tags on all these pages or?

Answer 1

You can use Schema.org on all pages.

Various consumers might find it useful. Why should they have to visit a specific page to see your Schema.org markup for content they already see?

Just make sure that you don’t create several items for the same thing on the same page, unless you denote them as being about the same thing (e.g., with Microdata’s itemid or by using the same subject URI in RDFa).

You could use mainEntity/mainEntityOfPage to denote which item the page is primarily about.