Palmistry is one of those grey areas when it comes to its governing laws and regulations in most countries. Normally it's the municipal laws and by-laws that you really have to look at. To read palms in one city may require nothing - Not even a business license. In another area you might need a business license and then have to make applications for additional permits as well, all prior to doing any paid palmistry work.
For example, in Santa Barbara California you have to look at Chapter 5.40 of their municipal code. There you'll find that palmistry is specifically listed as one of the "fortunetelling" practices that requires an "appropriate business tax".
The Santa Barbara Independent: We’ve all seen the signs for Madam Rosinka’s fortunetelling businesses, but other than that, we’re no Salem. Or so it seemed before reading Chapter 5.40 of the Santa Barbara Municipal Code.
Not that such practices are discouraged — rather, they’re perfectly permissible, so long as the magician pays the appropriate business tax. Among the professions for which a permit is required are astrology, palmistry, phrenology, life reading, fortunetelling, cartomancy, crystal gazing, and clairvoyance. You think that’s a comprehensive list? No. There’s also clairaudience, magic, necromancy, psychism, psychometry, mind reading, mental telepathy, automatic writing, spirit writing, trance mediumship, and sandgazing. If you’re reading this and asking, how could they have forgotten potion making in this list, rest assured — they didn’t. They also included materialization, ballot reading, conducting trumpet séances, prophecy, augury, divination, and the making of “magic articles.”
For anyone considering palmistry as a profession, it's just one more example of why you need to carefully check out the laws and licensing requirements in your exact area ahead of time.