Poetry in verse is - by my understanding - rare: very rare.
I have a thing which I recognise as poetry - I can point at the passages where it occurs; and this thing is seldom found. Most 'poets' never once achieve it, and among the true poets, it is only ever to be found occasionaly or intermittently (and of some, I cannot decide).
But poetry in prose can happen too. How may it be defined? Well, most prose - almost all prose - is about things; but poetic prose is the thing itself: poetic prose is that which it describes.
Many writers strive for, or contrive to, impersonate poetic prose, by rhetorical tricks. And they may 'fool' us for a while (and the prose writers may also fool themselves that they have actually achieved poetry); but genuinely poetic prose is far beyond most prose writers, and repeated reading will reveal this, if it is allowed to.
The main repository of poetic prose in the English Language is in the Authorised ('King James') Version of the Bible. And there is also some in Shakespeare's plays. From the next generation, the 'Centuries' of Thomas Traherne stand-out. In the modern era, if we compare CS Lewis and JRR Tolkien; it seems clear to me that Lewis never writes poetic prose, but Tolkien sometimes does.
Interestingly. I first became aware of the distinction between poetry and prose in the prose writings of Roberts Graves (such as The White Goddess) - yet Graves's own prose is always prosaic (superb in quality, but always 'about' - never 'it' - and indeed the same applies to his verse: it never rises to real poetry (although Grave's himself hotly asserted otherwise).
My understanding is that real poetry, whether found in verse or in prose, is rare, intermittent, uncontrollable, and only somewhat related to overall literary quality (some genuine poetry is found among minor poets like WH Davies or Walter de la Mare, while absent from major writers like WH Auden or TS Eliot).
We live on prose, it is our bread-and-butter - our staple diet - but poetry is there if we are open to it. What poetry 'does' is hard to say; mostly it points to the sheer possibility of itself - of language also being what language is about. A world where people communicated in poetry rather than prose would certainly be a better place!