Node Clone operation/tab missing for webform
Besides simply enabling the Node Clone module and checking the permissions associated with it, you'll need to select which content types can be cloned.

To do so, go to /admin/config/content/clone


After enabling for the "webform" content type, you should see the clone link available near the contextual link / action tabs at the top of a webform page when signed in as an admin and viewing the page.