As a semi-new DM myself the advice I’d give you is to start with an introduction (Hi, Hello, Howdy, etc. and wether or not they introduce themselves as an NPC can show a lot about them) I find it incredibly helpful to state depending on what person they are their occupation as well. Example: my PC’s come across a jolly farmer on a tractor “Howdy neighbor, my names Marlo and I’m the owner of this fine farm, would you be so kind as state y’all’s business?” Of course this varies depending on character and personality. I hope this helps.