MediaWiki:Apihelp-managetags-param-operation/en

Which operation to perform:
 * create:Create a new change tag for manual use.
 * delete:Remove a change tag from the database, including removing the tag from all revisions, recent change entries and log entries on which it is used.
 * activate:Activate a change tag, allowing users to apply it manually.
 * deactivate:Deactivate a change tag, preventing users from applying it manually.