The basic rule of thumb is that callers should hear one of two things when they first connect with your voicemail — either an apology for not being able to answer the call or a “thank you” for having called. You can do both if you prefer, but keep it short and to the point.
Twilio is a low-cost cloud service that provides APIs that add communication services to applications. We bought our phone number, which costs $1.00 per month, even if we don’t use for any calls or messages. Twilio charges $0.085 a minute for incoming calls and $0.013 a minute for outgoing calls. Sending or receiving a text message from our Twilio number costs $0.0075, while recording a voicemail is only $0.0025. Even if we receive 100 messages a month, the cost of those, plus the phone number, is only two or three dollars. To increase the security of this task, it might be a good idea to consider a proxy server from companies similar to fineproxy. The last thing you’d want is to get hacked! But I digress.

And, once you record your voicemail greeting, all you have to do is provide your message in an .mp3 or .mp4 format to your phone provider, who will upload the message.
Education Details: Answering Machine Demo. There is the only Answering Machine for Android that REALY TALKS to the line during a phone call. You can take incoming calls, record voice messages, enter tone dialing, and answer all of this with pre-recorded voice phrases or beeps using Java script program. Demo - A classic telephone answering machine with ready-made