Hi Cassino,
This is a difficult question to answer.
It depends on your computer skills and what you are willing to learn.
You can use simple drawing tools, word processing, professional drawing tools, text editors or even dedicated track layout programs.
A simple drawing tool could be like Microsoft Paint (if you are on a Windows computer).
Professional drawing tools could be like Adobe Photoshop (this costs money to buy).
Word processing tools such as Word can be used but it would be VERY CLUMSY.
If you are a computer/software enthusiast, you can even use notepad to 'draw' your image using the alphabet characters (search ASCII art on google).
There are dedicated track layout programs online that are free. I think this would be the best option if you want to be able to draw complicated layouts.
-plarnold