Show that you’re human! Not everything in business needs to bland and boring. Add some personality to your voicemail while still maintaining professionalism. Do you have a fun fact about yourself or something unique to you? Share that in your voicemail and then ask for the customer to leave you with a fun fact so that you can call them back.
Extension mailboxes enable businesses to share a group of mailboxes, but route incoming calls to one main voicemail number. They include a primary mailbox and up to nine (9) additional boxes. Each has characteristics of standard voice mailboxes and must be activated by an authorized user before they can be used. Once activated, log in to the mailbox, change the PIN, record your greeting and your name.

Context does matter here. If the caller would reasonably expect you to answer the phone (such as if they were calling a store or other place of business), an apology for not being able to get to the phone makes the most sense.
“Hi, you’ve reached [your name]. I’m away from[date] to [date]. If you need help with [X] before then, please contact [name] at [phone number]. Everyone else, please leave your name and number and I’ll return your call when I return. Thanks and have a great day.” “Hello, you’ve reached [your name]. I’m currently [exploring Asia, hiking through the jungle in Costa Rica, hanging out on the beach in Bermuda] — or more likely, [recovering from extreme jet lag, googling ‘Are red spiders poisonous,’ or looking for SPF 150 sunscreen] and won’t be back in the office until [date]. Leave your contact info and reason for calling and I’ll get in touch then.” “Hey there, this is [your name] from [your company]. I’m out of the office until [date]. In the meantime, please direct your inquiries to [coworker’s name] at [email address]. [He, she] can also be reached at [phone number]. Thank you.”