If you have a Uniden DECT 6.0 1760 series phone then unfortunately it has no inbuilt answering machine function.
You need to set up a voicemail service with your phone service provider. Go to your phone service provider's website to find out how this is done
Here is a link to the User Manual for the phone showing how to program the phone (scroll down the page to find Setting up Voicemail access) once you have setup the voicemail service with your phone service provider."
I had no idea how to record my greeting on this phone but the 1st answer worked for me. Listened to the messages, pressed 8, recorded my message, pressed 8 again, listened to the recorded message and hit End. It worked, yay.