This step is not mandatory, although an applicant may need a criminal record check if he or she intends to come to Canada as a student. If required, he or she will have to obtain a police certificate from each country or territory where he or she has lived for six or more months consecutively since the age of 18. Police certificates are required to determine if applicants have a criminal record. They also help visa officers make sure applicants are not a security risk to Canada.