In Ubuntu/Linux, It is not so easy to draw flowchart and diagrams. Thanks to draw.io - free online diagram software for making flowcharts, UML, process & network diagrams..etc.

Very easy to use and highly recommended!

Are you looking for MS Paint like application in Ubuntu/Linux?

Found a nice web-based classic MS Paint remake jspaint.app for drawing and editing images.

Hats off to creator of this!