A social security card is an official document issued by the U.S. government that contains a unique nine-digit number assigned to individuals. This number is used primarily for tracking earnings and benefits within the Social Security Administration, which manages the country's social security program. The card is essential for various purposes, including applying for jobs, opening bank accounts, and accessing government services. The social security number (SSN) on the card helps to identify individuals in the system and is crucial for tax reporting. It is important to keep the card safe, as sharing the number can lead to identity theft. Individuals can apply for a card through the Social Security Administration by providing necessary identification documents.