Canadian immigration applicants who wish to receive their Canadian permanent resident visa, and who are 18 years of age and older, must undergo a security clearance to prove that he or she is not criminally inadmissible to Canada. Police Clearance Certificates (or certificates of non-criminal activity) must be obtained from the country of current residence and from each country in which the applicant has resided for more than six months since their 18th birthday.
Police Clearance Certificates can usually can be obtained through law enforcement offices, government agencies or third party government-accredited companies. In extenuating circumstances, Canadian Immigration Visa Offices will waive the requirement to submit Police Clearance Certificates.
Police clearances can be completed using you personal information of biometrics (fingerprints). If your country offers fingerprint searches, you must use that method for the Police Clearance check. A letter from Immigration Canada (IRCC) may be required to submit to the overseas government office to get permission to conduct a search for immigration purposes.
For the country the individual currently lives in, the police certificate must be issued no more than six months before you apply.
For countries where the individual has lived for six months or more, the police certificate must be issued after the last time you lived in that country.

If your certificate is in a language other than English or French, it must be sent along with the original copy of a translation done by a certified translator.

All applicants for Canada immigration must also undergo a background clearance to screen those who have been, or are involved in, espionage, subversion, or terrorism. This is to ensure that the safety and order of Canadian society are maintained and protected. Such security screening decisions are made based on information from every available source, which is then carefully weighed to determine whether an applicant is likely to threaten the internal security of Canada. When there is an indication of security concerns, an interview will be scheduled to discuss these findings with the applicant. Anyone who poses such a threat must necessarily be prevented from entering Canada.