freelance work like adviser, consulting, programming, remote administration, web design, works than you only need a internet device to work from everywhere.

If you are in Thailand but you work from internet to another country (not your country), are you doing something illegal about Thai law?

I already check this in another countries that I lived and all the time since you can't apply for a work permit taxes, with international work except when the company have legal representation, and since services are usually exempted of taxes

but if you are in Thailand and you work from internet (remotely) to a Thailand company?

or if you are not in Thailand and you work to a Thailand company from another country (not your country)?

I've been working 6 years in this way, 2 from Thailand, but never to a Thailand company, I do not need nor waiting to work here because the prices/conditions are a bit low for me vs. I don't know so much thai, but you never know, recently I submit a list of my skills but nothing like a real resume, the same offering services but I will remove that depending on the Thai law, I don't want immigration problems for only a few bucks.

Working in Thailand requires a work permit. Thai labour laws where not set up with the inetrnet in mind, so your position is a difficult one. Most people choose to fly under the radar, when working over the internet for a foreign business. In case of working for a Thai business that would be difficult.

since services are usually exempted of taxes

Don't think so.