A personal identification number, or PIN, is a unique numeric code used to verify a person's identity. It is commonly used in banking and electronic transactions to provide an extra layer of security. Users typically create their own PIN to access accounts, ATMs, or mobile devices. PINs usually consist of four to six digits, making them easy to remember but challenging for others to guess. It is important to keep your PIN confidential and change it regularly to protect against unauthorized access. Many systems also offer additional security measures, such as two-factor authentication, to enhance safety.