For most Library-licensed content, the URL displaying in the browser's location bar is NOT a persistent URL; that URL may bring back that content for a few hours, a few days, a couple weeks, but eventually it will go away. So the persistent link must be found.
'Permanent' or 'persistent' or 'durable' are all terms for a link that is permanent rather than generated on the fly by a database.
The vendors from which the Library licenses content aren't consistent in how they provide this function.
Many vendors do have an icon on their pages to signal where to find the permanent URL.
Sometimes it's the share icon
and sometime its a link icon
and sometimes something completely different:
Clicking the share icon or the permalink icon opens a dialog box where the persistent link is presented.
Copy that link.
The DOI ((Digital Object Identifier), e.g. 10.5699/yearenglstud.46.2016.0242 ) may also be used as a persistent link to an article.