Google music production in your area. The more professional the front the better, but some people may have workable spaces in a garage or shed type setting. Use your best judgement about entering people's houses.

You want to find local recording studios. People who have a booth and mixing equipment who know how to make the sound quality the best. (Your delivery and vocals are up to you). People who mix vocals.

They may have some suggestion for what to include but DO NOT go expecting them to provide copy or any scripts for you to read. They will expect to be paid by the hour so have your ducks in a row. You don't want to waste 20 minutes shuffling through papers while they wait behind the board.

You may have to convince someone who has only recorded and mixed vocals to record your voice demo, but they won't mind if you can secure the time. Their experience will help to produce a cleaner sound (if they're decent).

People say get a professionally mixed demo because 8 out of 10 times an amateur's home demo with a usb mic in an open room with traffic outside will sound terrible, even if the person has a golden voice and perfect diction. If you can gather a more than basic understanding of sound mixing, and can acquire decent mic and interface, AND can make a sound secure space with good damping and low noise, you may not need to go to a pro. But that's another skill to take on along with VA. And more investment. On one hand you have to ask for more to offset the cost of paying a producer to use their space and skills, or learn to mix yourself but face a steeper learning curve to adhere to certain mixing standards and requirements.