How do I enter the Euro symbol? Ubuntu

The easiest way to enter the € Euro Symbol via shortcut is the following:

Go to Settings> Keyboard > Keyboard Shortcuts: View and Customize Shortcuts

Click Customized Shortcuts

Create two shortcuts, one for the Dollar Sign and one for the Euro sign.

Command: xmodmap -e "keycode 13 = 4 dollar 4 dollar"
Shortcut: Ctrl+Alt+D

Command: xmodmap -e "keycode 13 = 4 EuroSign 4 EuroSign"
Shortcut: Ctrl+Alt+E

Now if you want, for example, to change the $ sign

Press Ctrl+Alt+D and then Shift+4

Now if you want, for example, to change the € sign

Press Ctrl+Alt+E and then Shift+4

Enjoy!