The 12 categories of authorized travel to Cuba are now (see also the US Embassy in Havana’s website):
“family visits; official business of the U.S. government, foreign governments, and certain intergovernmental organizations; journalistic activity; professional research and professional meetings; educational activities; religious activities; public performances, clinics, workshops, athletic and other competitions, and exhibitions; support for the Cuban people; humanitarian projects; activities of private foundations or research or educational institutes; exportation, importation, or transmission of information or informational materials; and certain authorized export transactions.”
Many individual and group travellers to Cuba will now seek to comply with the ‘Support for the Cuban People’ general license. To see information about compliance under ‘Support for the Cuban People’ in particular together with some helpful examples, please refer to §515.574 of the Code of Federal Regulations here.
There is more information about traveling to Cuba on the US Treasury’s website here (FAQs related to Cuba, Section II).