The laws and even the industry is not standardized. Though things are working their way to being more consistent. You should definitely be certified before taking payment for training clients or teaching classes. But to know for sure the regulations in Texas you should contact your state government. In Hawaii I need to register my business and obtain insurance as well as a business license. In Colorado I also needed to these things. I found the right place to contact by searching “starting a business in … Hawaii… Colorado” and got the information I needed very easily. I would caution you not to be fooled by sites that are not official. All the sites I visited in my search were .gov sites. There were several unofficial sites that popped up on the search.