Job Recruitment Website - Ranking of immigration countries - From b 1 to f 1, you need to write to the immigration office to apply for a family visit visa and transfer to a student visa. How to write? What format? Ask the great god for guidance

From b 1 to f 1, you need to write to the immigration office to apply for a family visit visa and transfer to a student visa. How to write? What format? Ask the great god for guidance

Normal letter format, here is the letter format/request for extension.

Write only your purpose and reason.