This is one of those subjects where you're going to get all sorts of answers depending on who you're talking to. And it's something that some people can get really into, while others dont take much interest in it or outright just dont like the concept.
I've never engaged with the idea too much myself, and only very recently decided to actually take a stab at making an original character of my own, which resulted in the images in these two threads:
https://www.autismforums.com/threads/my-best-bit-of-art-so-far.43021/
https://www.autismforums.com/thread...en-working-on-would-love-some-feedback.44141/
They're both the same character though the style seems a bit different sorta because it turns out I have no idea what I'm doing, I'm just winging it here...
Right now though, that's as far as it goes. I drew two pics of her and named her Iris, and that's all I've done so far. No personality or traits or background or anything like that... just those two pics. So that's my own personal example.
Usually most people who make OCs seem to enjoy going into those aspects, and I might do so myself, but it was hard enough getting this far, I dunno how I'd be at actually fleshing out a character beyond the appearance. Never been much of a writer. Probably.
And of course for some people, a given character might only exist as text, with no picture.
That's sorta my limited grasp of the concept at this point. I dont actually engage with the online art community like, at all, so my knowledge is limited.