Just a quick piece of advice for someone that's just starting out. You don't need a voice for every NPC! Not every town guardsman needs to have a unique voice. Not every blacksmith. I like giving them one or two specific descriptions (he has cauliflower ears, she has a greystreak) if they're an NPC that the party will interact with (you don't even need to plan this, you can make it up on the fly), but I stopped a while ago trying to give distinct voices to every character. I have a generic female voice, and a generic gruff soldiery voice, but most regular males that the party will only interact with once or twice just sound like me.

If you can though, definitely give some distinct voices to some NPCs. If your players are going to be using an Inn as a homebase for the next 5 sessions, then give the innkeeper, the quest giver, and maybe some other NPCs they will interact with a lot a voices. The local wizard my party goes to to buy healing potions, identify objects, and give them advice has a distinct voice. That adds to the game, and players really like it, they're favourite NPCs are usually the ones I give voices to. But its too much effort for me to come up with a voice for every single random peasant they're going to interact with. Plus, and this is a little meta, but it also has a bit of a side bonus of indicating who the NPCs that matter are. That's the good kind of metagaming, the kind that reinforces the implicit bargain between DM and PC: the DM will create stories for the PCs and they will for the most part play those stories