The Social Insurance Number (SIN) is a 9-digit number issued by the Canadian government needed to work, file taxes, and access government programs in Canada. You can find your SIN in several ways:

• On your SIN card or the Confirmation of SIN letter issued by Service Canada.
• On Canada Revenue Agency (CRA) documents such as income tax returns, tax slips, records of employment, or RRSP contribution documents.
• By logging into your My Service Canada Account (MSCA) where you can view and print your SIN digitally.
• If lost, you can get a replacement SIN confirmation letter by applying at a Service Canada center in person, online, or by mail.

To apply or view your SIN digitally, you can register or sign in to MSCA via the official Canada.ca website. New SIN applicants can apply online or by visiting a Service Canada location with required documents proving identity and status.