You will need to apply for an Authorization To Return To Canada (ARC) if you have previously been asked to leave. This is a formal way to ask the Canadian Government for permission to re-enter Canada.
How do I know if I am in need of an ARC?
This is dependent on the type of removal order that you were issued. If you were asked to leave Canada odds are that you will require an ARC to return however this is often not a stand alone process and is often paired with other types of applications.
Canada has 3 kinds of Removal Orders
1. Departure Order
If you received a Departure order and you left Canada within 30 days and verified your departure with a Canadian Immigration Officer at the port of exit then you do not need an ARC and you may return to Canada subject to normal examination at the port of entry. It is however important to note that if you were issued a departure order and left Canada without verifying your departure or left Canada more than 30 days after the Departure Order was issued then the Departure Order automatically becomes a Deportation Order and in this case then you do in fact need to apply for an ARC.
2. Deportation Order
If you received a Deportation order then you will definitely need to apply for an ARC. If you were reported because of criminal inadmissibility then you will need to apply for criminal rehabilitation before applying for the ARC. You may also need a Temporary Resident Permit (TRP) to be allowed to enter into Canada.
3. Exclusion Order
If you were issued an Exclusion Order and 12 months have not passed since you left Canada and you have a certificate of Departure (IMM 0056B) showing the date you left Canada then you do not need an ARC and you may return to Canada subject to normal examination at the port of entry. If you were issued an Exclusion order and 12 months have not passed since you left Canada then you need an ARC if you want to return to Canada less than 12 months after the exclusion order was issued.