How's it going is a relaxed way of asking whether somebody is well. All right, how's it going.
It expects fine or not bad rather than an actual account, which is what makes it a greeting rather than a question. It is informal and works with people you already know.
1phrasehow's it goingA relaxed way of asking whether somebody is well.
“He put his head round the door and asked how's it going.”
how's it going is a greeting.
Practised in Small Talk & Everyday Phrases