The CBU (Clave Bancaria Uniforme) is a unique 22-digit identifier for a traditional bank account (held at a regulated bank). The CVU (Clave Virtual Uniforme) is the equivalent 22-digit identifier used for virtual accounts held by FinTech companies or payment service providers. Both codes function similarly for receiving transfers.
Sources: https://www.bcra.gob.ar/mediospago/Clave-Virtual-Uniforme.asp and https://www.bcra.gob.ar/mediospago/Clave-Bancaria-Uniforme.asp

