Appearance → Customize → Site Identity → Tagline, and the Display tagline switch below it.
Where it shows
Under the site title in the header, in the meta colour — quieter than the title, deliberately. On a dark header skin it is lightened along with the rest of the bar, so it stays a step below the title rather than turning invisible.
It prints only when both are true: Display tagline is on, and the tagline field is not empty. A fresh WordPress install ships with “Just another WordPress site” in that field, which is worth replacing or clearing before the site goes public.
Writing one
A tagline in a header has about four words of the reader’s attention. The ones that work say what the publication covers and for whom:
- Local news for the Clyde valley
- Reporting on Bristol’s housing crisis
- Essays on maps, borders and place names
The ones that do not work describe the website rather than the work — “Your number one source for news”, “Thoughts and ideas” — or repeat the title in longer words.
If nothing true fits in four words, leave it off. An empty tagline is not a missing feature.
SEO and feeds
WordPress uses the tagline in a handful of places outside the header — the RSS channel description among them — so the field is worth filling in even with Display tagline switched off. Turning the switch off hides it from the header only.
With an image logo
If your logo already contains a strapline, turn the tagline off: two straplines stacked read as a mistake. See logo and site title.