Website: https://www.mightycall.com/blog/the-best-services-to-record-a-voicemail-greeting-for-business/
Extension mailboxes enable businesses to share a group of mailboxes, but route incoming calls to one main voicemail number. They include a primary mailbox and up to nine (9) additional boxes. Each has characteristics of standard voice mailboxes and must be activated by an authorized user before they can be used. Once activated, log in to the mailbox, change the PIN, record your greeting and your name.

Phone prompts are used in all types of telephony applications. Commonly called “Voice Recordings”, these scripted announcements help callers navigate options using their phones. Whether choosing a preferred language, locating support assistance, or utilizing self-service to access account information, phone prompts can be customized in any configuration. Day & Night Greeting Department Options Account Information Store Locator & Directions Foreign language options
Having experienced multiple "small business phone systems" (AT&T hard wired system - OK, AT&T SynJ wireless system - TERRIBLE, and a vTech system - almost as terrible) and for basically the same price plus a little bit of configuration time, the Grandstream products worked better, had more features and had much better sound quality than the others. I hope this helps. I bought this system for my office due to the affordable price. It initially had some problems with calls cutting out and poor call quality. I was going to return it, but the quality improved for a short while. The problems came back a week later and I had my phone guy look into the phones, wiring, and telecom installation. He said everything else was good but there was a problem with the phones. We hooked up a different system and viola! No more problems.