If you are using the Gnome DE and don't use Online accounts at all you can remove the package itself with sudo apt-get remove gnome-online-accounts if you want to remove the entire package along with any configuration data you can use the command sudo apt-get purge gnome-online-accounts
Open a terminal and check which account plugin packages are installed :
dpkg --get-selections | grep account-plugin
sudo apt purge account-plugin-flickr libaccount-plugin-flickr
sudo apt purge account-plugin-google libaccount-plugin-google
Update addressing the requested information in the comment below
In earlier editions of Ubuntu (14.04/16.04) the
libaccount-plugin
packages don't exist, soto remove the Flickr account plugin execute :
sudo apt purge account-plugin-flickr
to remove the Google account plugin execute :
sudo apt purge account-plugin-google
If you are using the Gnome DE and don't use Online accounts at all you can remove the package itself with
sudo apt-get remove gnome-online-accounts
if you want to remove the entire package along with any configuration data you can use the commandsudo apt-get purge gnome-online-accounts
Source:
https://www.howtoinstall.co/en/ubuntu/trusty/gnome-online-accounts?action=remove