A plain-language explanation
The robots meta tag provides search engines with page-level instructions about indexing and following links. It does not guarantee that a page will be indexed.
Where it helps in practice
Meta robots provides page-level directives when a crawler can fetch and read the document head.
The decision before implementation
Choose index/noindex and follow/nofollow explicitly and avoid conflicts with robots.txt, X-Robots-Tag or canonical.
How to verify the result
Inspect rendered HTML, server response, URL inspection and state after reprocessing.
