Apply for the CMA exam. After completing a medical assistant program you must fill out an application, which can be downloaded and printed. Your application should be received by the AAMA three months or 90 days before your preferred 90-day testing period start date.pply for the CMA exam. After completing a medical assistant program you must fill out an application, which can be downloaded and printed. Your application should be received by the AAMA three months or 90 days before your preferred 90-day testing period start date.