What we both referenced is the program known as CAN+ for visitors of some countries who have been to Canada in the last 10 years or who have a valid U.S. visa. When applying through CAN+, the applicant only needs to submit proof of travel to U.S. or Canada and can submit fewer proof of financial support. The program is only available at certain visa offices or for nationals or legal residents of certain countries.
There is no separate application form; rather
How do I know that my application can be processed under CAN+? What supporting documents should I submit?
Visa application centres will screen all applications for CAN+ eligibility. Applications that show that the applicant travelled to Canada in the last 10 years or holds a valid U.S. non-immigrant visa will be sent to the visa office for expedited processing.
Check the document checklist for full details of what you need to submit with your application.
As you found in Canada’s Singapore visa office, on page 1 of the document:
CAN+ Program: Proof of previous travel or valid USA visa
If you have travelled to Canada in the last ten (10) years or currently hold a valid United States of America non-immigrant visa, provide proof of this Canadian travel or valid USA visa (entry stamps in passport, proof of the valid visa).
In other examples, the CAN+ program is available to nationals in Mexico, and India. In France, CAN+ has the requirements vary slightly:
- Have previously been issued a Temporary Resident Visa to Canada in the last five years; and
- Have had NO immigration infractions (for example: deportation, refused visa, inadmissibility…) in ANY country
- Be a legal Resident (in other words to be legally residing) in the country where they are living.
See also Wiki: Visa Policy of Canada