I want to stay in Thailand for one year, which VISA that I should apply for. I am from Taiwan?
Please know that a 1 year visa is only applicable for those who are employed with a work permit in Thailand, foreigners on retirement or those married with a Thai national. Foreigners who are also enrolled in an institution may also be granted initially a 90day ED visa or 1 year ED visa.
Note that they have become very strict with the educational visa and if you want to extend it beyond the 1 year you will need to show results from a university or the ability to speak basic Thai if you enrolled for a Thai language course.