NotePad++ is a free and open source text editor for Windows. It is written in c++ and released under GNU General Public License. It is based on Based editing component Scintilla, Win32 API and STL. But you can still install NotePad++ on your Ubuntu Linux system via the snap store. The snap app comes pre packaged with Wine setup. So the app will run on any Linux system.
You can also try below NotePad++ alternative.
Notepad Next Re implementation of Notepad++
Install NotePad++ on Ubuntu
Open the terminal command-line application (ctrl+alt+t) and run below NotePad++ snap installation command. It will install the latest version of NotePad++ on your system.
sudo snap install notepad-plus-plus
After the installation you can run the app from the application menu or via below command in the terminal app.
And you can also uninstall NotePad++ using below command.
sudo snap remove notepad-plus-plus