The Canada Border Services Agency (CBSA) collects basic biographic information on travellers entering and exiting Canada by land and air. The agency now records your complete travel history information to further enhance border management and security.
The CBSA shares entry and exit information with its federal partners, including Immigration, Refugees and Citizenship Canada (IRCC). This means IRCC will be able to verify exactly how many days you stayed in Canada.
This can affect your applications for immigration papers, such as Canadian citizenship application, permanent resident card renewal (PR card renewal), etc. These applications require you to reach a certain amount of time lived in Canada prior to applying.
More information: https://www.cbsa-asfc.gc.ca/btb-pdf/ebsiip-asfipi-eng.html