The MPIN in GCash stands for Mobile Personal Identification Number. It is a 4-digit code that acts as a password to access your GCash account. This code is used to sign in to your account using the GCash app and to authenticate payments made from third-party services or websites. Additionally, it is used to verify your identity when settling a payment using GCash via third-party merchants and websites. The MPIN was also previously used by GCash Mastercard holders to withdraw money using ATMs, but this has changed after card PINs were updated to 6-digit codes. If you forget your MPIN, you can recover it using the "Forgot MPIN" feature in the GCash app, where you will receive a six-digit recovery code to enter and set a new four-digit MPIN.