You can use either the Galaxy S10's Phone app or a visual voicemail service to set up a voicemail greeting on a Samsung Galaxy S10.

You can set up voicemail on your Android phone directly from the phone's keypad or its Voicemail app if it features one.

Most people that buy a modern Android phone expect it to work out of the box with minor tinkering. That's also true of various phone features, like reliable connectivity, performance, and storage. But ...