How to remove php-mbstring from Debian 9 (Stretch)

Uninstall php-mbstring

To remove just php-mbstring package itself from Debian 9 (Stretch) execute on terminal:

sudo apt-get remove php-mbstring

To remove the php-mbstring package and any other dependant package which are no longer needed from Debian Stretch.

sudo apt-get remove --auto-remove php-mbstring

If you also want to delete configuration and/or data files of php-mbstring from Debian Stretch then this will work:

sudo apt-get purge php-mbstring

To delete configuration and/or data files of php-mbstring and it's dependencies from Debian Stretch then execute:

sudo apt-get purge --auto-remove php-mbstring