Mobile phone card, are there any two numbers that send text messages to each other or make phone calls without charge? What business do you need to do?

There is no free service, and there is no such service for SMS. If you want to send text messages, you should apply for a monthly SMS subscription. Callers can apply for a home number, sometimes with a long limit every month. In other words, you can exchange calls freely for a certain period of time. The average time is 4000 minutes per month. In fact, such a long time is equivalent to free.