The My Client Centre, otherwise known as a client manager account or an MCC, is an umbrella account containing access to individual Adwords accounts and other client manager accounts.
The client centre contains numerous benefits, though is only available by becoming a Google Advertising Professional. (Hence why I am studying for my exam!)
Your MCC features a ‘dashboard’ view of your managed accounts, with alerts available for all important account issues, and provides easy access to robust performance reporting tools.