Most businesses will automatically play a recording if you try to call their office when they are closed. An after hours announcement is a professional way to notify callers of important details, rather than making them wait for the call to failover to a voicemail box or other destination.
A group greeting is for the general mailbox associated with a phone number. From your business phone, press *98. Or, from any phone, call your business phone number, and then press * to skip the voicemail greeting. Enter your mailbox PIN. For mailbox settings, press 4. For greetings, press 3. To record a personal greeting, press 1 .

32. Hi, you’ve reached [your name] at [your company]. I’m away from my desk. Please leave your name, number and a message, and I will get right back to you.
“Hi, you’ve reached [your name] at [your company]. I’m unavailable right now — probably helping [type of company] get [X results, e.g. ‘double their leads in 60 days,’ ‘hire the best and brightest engineers,’ ‘convert 40% more customers.’] Leave your name and number, and we’ll discuss how your company can see similar results.” “Hello, this is [your name] at [company]. Thanks for calling. Please leave your name, number, and reason you’d like to chat, and I’ll get to back to you ASAP.” “Hi, you’ve reached [name] at [company]. If you need a quick response, please shoot me an email at [insert email address] and I’ll be in touch by EOD tomorrow. If it’s not urgent, leave me a message with your name and number. Have a great day.” “Hey, this is [your name]. If you’re calling for [X reason], please [contact so-and-so] or [go to our website, send me an email]. For all other inquiries, leave your name and a brief message and I’ll call you back within [one, two, three] business day[s].” “Hello, you’ve reached [name] at company. I’m unable to come to the phone right now. Leave your name and number, and I’ll return your call as soon as I’m free. Thank you.”