The simple truth is that you need to be more aware of what you’re leaving for other people to hear. Sure, this doesn’t always register as a priority for users, but it’s never too late to reassess your greeting. a. Reading/Speaking in the Imperfect Tone: Tone is absolutely everything. Users don’t want to come off as being too nice, as it sounds insincere, or being too terse, as it can be interpreted as being rude. That being said, striking the right balance is absolutely essential. Your greeting exists as its own entity, and therefore, it should NOT rely on callers’ familiarity with you. Instead, it needs to appeal to the masses. As such, your inflection, i.e. the way you state your name and directions, needs to be both welcoming and firm. b. Injecting Humor & Insincerity: While humor/light heartedness can be welcoming, it can also convey a sense of informality, insincerity, and ultimately unprofessionalism. Why, because you’re not there to lend your humor or to contextualize. Instead, you’re assuming the caller has a working knowledge of your personality to ground the message. Though this might not sound like it’s all that terrible—it can be detrimental. As stated above, one should NEVER rely on a caller’s familiarity with you. Instead, aim to appeal to the masses. Humor is ultimately subjective, meaning not everyone has the same tastes; therefore, someone is bound to be turned off by a quirky or off-color remark. While implementing a light-hearted or even tongue and cheek tone can work, it’s just a really bad idea.
A name recording is the most basic way to personalize your voicemail box. It inserts your name into the default unavailable greeting: “The person at mailbox [four-digit voicemail box number] is unavailable. Please leave your message after the tone. When done, hang up or press the pound key.” Dial *98 on your OnSIP-registered phone. Enter your voicemail box number. Enter the PIN/password for your voicemail box. Press 0 for voicemail box options. Press 2 to record your name. Default Unavailable Greeting

More information can be found at Set up Cloud PBX voicemail - Admin help. Let your users and helpdesk know Don’t forget to inform your users and your helpdesk. The page Check Skype for Business voicemail and options, describes how users can set up and use their voicemail. Make sure users are familiar on how to use it, and that your helpdesk
Don’t include the date unless it’s completely necessary. 16 of the messages I heard last month had the wrong date—one of the messages had a date over 2 months old!