If you had ever used windows operating system, must have used the inbuilt snipping tool(included in windows vista or later) by which you can take screenshots. Likewise being a Ubuntu user you are wishing to use a free tool which can help you to take screenshot , i will help you to install the tool through my tutorial. Shutter is free and popular screenshot tool which you can install in your Ubuntu system.
Note: Shutter is no longer available in Ubuntu Software since Ubuntu 18.10, because some old Gnome libraries required by the screenshot tool have been removed from Ubuntu universe repositories.
Open terminal and run the below command to add the PPA, you can switch to your root login by running sudo su or while running the below command you may get to enter your password so type your user password accordingly.
sudo add-apt-repository ppa:linuxuprising/shutter
Then install Shutter either via Synaptic package manager or by running command in terminal:
sudo apt install shutter
It will take few time to install the application, once installed launch shutter from gnome software menu and enjoy.
How to Uninstall/remove shutter application.
To remove shutter, simply open terminal and run command:
sudo apt remove –auto-remove shutter
Or go to your software and updates from main menu and–> Other software and remove Shutter.