Shutter, an excellent screen capture tool, is no more part of official Ubuntu repository. Hopefully, there's a solution :
(Source : https://www.linuxuprising.com/2018/10/shutter-removed-from-ubuntu-1810-and.html)
sudo add-apt-repository ppa:linuxuprising/shutter
sudo apt-get update
sudo apt install shutter
(Source : https://www.linuxuprising.com/2018/10/shutter-removed-from-ubuntu-1810-and.html)