A favicon is a small thing that is disproportionately visible. It is in the browser tab, the bookmark bar, the history list and the phone home screen, and its absence — the blank page icon or a generic globe — is one of the few visual cues that reads as a site not being finished.
This is the narrowest subject here, and the articles cover it between them.
One article is about adding a favicon properly. WordPress has a built-in site icon setting that generates the sizes modern browsers and devices ask for, which is almost always the right route. The article covers the source image requirements — square, large enough, legible when scaled to sixteen pixels — because a logo that works on a letterhead usually does not survive that reduction.
Another is the problem everyone hits: you changed the favicon and the old one is still there. That is almost never WordPress. It is a browser cache, a CDN edge, or a service that fetched the icon once and kept it, and each needs a different nudge.
If your favicon looks wrong right now, the article on a favicon that will not update is the one you want.
Trace a missing or stale WordPress favicon from the active Site Icon through rendered tags, direct file responses, CDN caches, service workers, and browser storage.
Add a clear, square WordPress Site Icon through one supported owner, remove duplicate favicon output, and verify the rendered files in real browser contexts.