11. Hello, you’ve reached [your name]’s cell phone. I can’t take your call at the moment, but if you leave a brief message, I’ll get back to you as quickly as possible.
After setting the number on your voicemail, you must also record a personal voicemail greeting. Follow the steps below. Start the Phone app. if you don’t see the numeric keypad, tap “Keypad” at the bottom of the screen. Tap and hold the “1” for about two seconds until the phone automatically calls voicemail. Immediately tap “3” to access voicemail settings. Listen to the options. On most voicemail systems, tap “2” to start the process to record a new greeting. The current personal greeting will play; then tap “2” again to record a new greeting. Say the greeting you want, and tap “#” when you’re done. To save the greeting, tap “1.” The personal voicemail greeting has been set. Hangup the phone. How to setup voicemail using a Visual Voicemail Applications

Much better & simpler method: simply phone your own voicemail service. Then one of the options will be to ‘record a voicemail’; after which you can enter the phone number, record & send voicemail.
Visual voicemail is an easy way to check your missed messages. You can see a list of voicemails along with the date it occurred and the length, and you choose which calls to listen to and delete.