A dead-friendly, everyday greeting that’s basically hi with a bit more warmth and familiarity. You chuck it at mates, neighbours, the postie, your nan, whoever. Depending on your tone it can be bright and cheery, or a cautious hiya when you’ve bumped into someone you’d rather not. Not formal, but not rude either. Works in person, texts, and phone calls.
"Hiya, you alright? Saw you in the chippy earlier but the queue was chaos. You still grafting loads, or fancy a quick brew?"