I am a prospective high school sophomore and will immigrate within six months. If I take a leave of absence during the six months before immigrating,

If you immigrate within half a year, you will only be in the second year of high school in China. Therefore, the Chinese high school cannot give you a graduation certificate. It can only issue you a study certificate and transcript, which is proof. You have studied in this high school, and your scores in various subjects are as follows. Study certificates and transcripts can be issued together. Then you can make this certificate notarized in Chinese and foreign languages. It would be better to make more copies and bring them to foreign countries for use when applying for schools.