Rehearse your greeting a few times before you press record. Plan your pauses and select natural places to take a breath. If you are recording directly into your phone don't hold it to your ear like you are talking on the phone. This can produce a muffled tone. Hold the phone out in front of you a few inches from your mouth for the clearest recording. This may require some trial and error. So playback your greeting and make necessary adjustments on your re-record.
The bottom line is that a business’s situation is likely to change often and rapidly, each of which need a unique and applicable voicemail greeting to cover the circumstances and timeline. For example, callers shouldn’t reach a business-as-usual voicemail, and therefore expect a return call within the business day, if the subject they’re calling is out on vacation for two weeks. Such a lack of communication is a recipe to lose that caller’s trust and tarnish the brand’s reputation.

Rather than waiting for a callback, open up additional channels of communication with your callers by inviting them to email. The most professional voicemail greetings often include an alternative method of communication.
To save voicemails on most Android phones: Open your Voicemail app. Tap, or tap and hold the message you want to save. In the menu that appears, tap the one that says “save”, “export” or “archive.”