如何申請美國陪讀簽證？

It seems like you don't know what you are trying to ask.

If you friend goes to the U.S. for teaching, she should have a visa sponsored by the employer. As most employment visa (including J-1) provide derivative applicant status, the spouse will be allowed to go with the principal applicant.

The exact application detail varies based on the visa.

If you friend goes to the U.S. for studying (F-1/M-1 and J-1), she will have to request derivative status from the school. The school will have to generate necessary document (F-1/M-1 - I-20, J-1 - DS-2019) and system entry (SEVIS), so that the spouse will have all necessary document for the visa.

For that, you will have to contact the school for detail, as school may impose additional requirement.