I am using Ubuntu 20.04 and I need you to suggest me an application to make simple and quick drawings.
I need the application to support common image formats and allow me to quickly add text, crop, scale, flip, and rotate.
The tools that I would use would be: pencil, selection, polygons, lines, text, rectangles and circles.
My suggestion is that you install Drawing, it is a drawing application that allows you to make simple and fast drawings.
Although it is open source published under the GNU GPL v3 license, it is not available in the repositories, and requires the addition of a ppa.
To install it, open a terminal and run these commands:
A good simple drawing package is Google Drawings
This is a webapp and requires no installation on your Ubuntu system.
just go to https://docs.google.com/drawings to get started.
I think Kolourpaint supports everything you need, and can be installed with just
sudo apt install kolourpaint