How do I change my voicemail greeting on Android? Open the Phone app . Press and hold “1” to call your voicemail. Enter your PIN and press “#”. Press “*” for the menu. Press “4” to change settings. Press “1” to change your greeting. Follow the recorded instructions. Access your main voicemail menu. Listen for instructions to enter your password. From the main menu press 3 for Personal Options. Press 2 for Greetings. Press 1 to Change Greeting. Press 1 to Record personal greeting or press 2 to select the standard greeting. Tap on Call settings and select Voicemail. Tap on Voicemail service and select My carrier or My operator. Tap on Setup, select Voicemail number and type in your voicemail number. Tap on OK in the Voicemail number changed popup.
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.

Many busy businesses utilize auto attendant greetings to make a great first impression, however, if your business relies on the personal touch of a live receptionist, it is important to have a plan in place when that position is unstaffed. Make sure your voicemail greeting contains the useful information that your receptionist would normally provide. This could include: location & directions, office hours, website URL, or social media info, as well as any pertinent company information.
When you leave a voicemail do not use your full name because that immediately raises a red flat that you are a salesperson making a cold call. Instead, say your first name only followed by your company name. This will make your customer feel that you are much more familiar with each other than you really are. Saying your last name would defeat the whole purpose of demonstrating familiarity.