The Binance ID or UID is a unique identifier assigned to each account. You need to provide your User ID for customer support issues. Follow the below steps to find it on the Binance website or App.
On Binance website:
Log in to your account and go to [Profile] - [Dashboard]. You'll see your User ID at the top of the page.
On Binance App:
Tap the [Profile] icon on the top left corner. You will then see your user ID next to your nickname.
