Hi dear @irastra,
Thanks a lot for your comment. Unfortunately my laptop screen doesn't flatten out, so I had to draw on it on a 90 degree angle.
If you can afford the ones that become flat or detach from the keyboard, it would make things a lot easier and would be more ideal for you drawing and posture too.
I used a sketchbook program. It has free part, but I imagine it will offer more tools if you pay for it.
Eventually, I will invest on these things.
Best of luck and I hope to see your art soon :D