Open class means that many enterprise personnel are trained in one place by training institutions, and enterprises can freely choose the number of participants, which is more suitable for the situation that the number of employees in enterprises is small and the per capita training cost is relatively small;
Internal training is specialized training conducted by training institutions within the enterprise, which is generally applicable to the situation with a large number of employees. If the enterprise involves a large number of employees, the per capita training cost can also be reduced.