It’s a good practice for each of your team members to have their own personal business phone numbers. There are many reasons why they shouldn’t use their personal cell phone number for business, so you’ll want to give them their own phone number through your VoIP provider or phone system.
Most voice mail users have a desk phone line, which rolls calls to a voice mailbox. Customers with virtual telephone numbers (TNs) do not have a physical desk phone for this number. If you use voice mail with a Cox virtual TN, refer to the tips listed below. If you have a virtual TN, the related voice mailbox should be pre-set by Cox voice mail teams. If you cannot access the box from a valid access number, contact a Cox representative to make sure that the mailbox is initialized. When you log in to the mailbox, you need to update the PIN, record a new greeting, and record your name. Use voice mail and features as necessary. Paging Notification

You can also upload an unavailable greeting using the OnSIP app. After logging in, click on the Voicemail Settings gear icon at the far right. Make sure that the Custom Greeting is toggled to "on." You will then see an option to upload a .wav file of your choice. This recording will serve as your unavailable message.
Do you speak a second language and serve customers in an area that primarily uses a language other than English? Make it known that you speak both languages. Start the voicemail with the most dominant language spoken in your market followed by the same message spoken in the secondary language: