Do we have to recruit new people to leave after the handover?

No, if you only need to leave your job three days in advance during the probation period, you need to resign one month in advance if you have become a full member. Within this month, if the company recruits another person, you can hand over the finished work and go. If the company doesn't recruit new people this month, you can leave after one month. Just leave the work to the leader when you leave. If you become a regular employee in a more formal company, you need to resign one month in advance.