Visage means a face — but it is a literary word, and choosing it instead of "face" changes the temperature of the sentence. Writers use it when the face is being read like a landscape or a sign: a stern visage, a pale visage, his visage darkened. Poems, novels, and old translations are its natural home. In ordinary speech it would sound odd, even comic; nobody says "wash your visage".

Because it belongs to writing, it tends to attach to a whole impression rather than to the parts. You would not describe someone's visage as having a scratch on the left cheek. You describe what it shows — mood, character, age, dignity.

A second, extended use is common in journalism: the visage of something abstract, meaning the outward face it presents. "The changing visage of the city." This is a deliberate stretch of the word, and it works because everyone can hear the metaphor.

You will meet visage most often in fixed literary settings — Shakespeare, hymns, fantasy writing, subtitles for period drama. Recognise it; you rarely need to produce it.