What does UCI number mean for Canadian visa?

What does the UCI number of Canadian visa mean?

The full name of UCI is the unique customer identifier, which is the only customer account of the applicant. The account number will appear on the official documents issued by the Immigration Bureau, such as visa, PR card, study or work permit, etc. The number consists of eight numbers, arranged as follows (for example, 0000-0000), and each applicant will have a UCI number after obtaining a visa.

Remarks:

When you first apply for a Canadian visa, you won't have a UCI number. Please fill in "Not applicable" under the corresponding form. If you can't enter N/A in the online application, you can leave it blank.