Install asterisk-voicemail by entering the following commands in the terminal:
sudo apt update sudo apt install asterisk-voicemail
simple voicemail support for the Asterisk PBX
Asterisk is an Open Source PBX and telephony toolkit. . This package includes the standard files-based voicemail storage. This is normally the one you use and is the one that will Just Work. The only reason not to install it is if you want to use a different Asterisk voicemail storage (ODBC or IMAP). . For more information about the Asterisk PBX, have a look at the Asterisk package.