National Identity Document
The 'DNI (Documento Nacional de Identidad)' is the Spanish term for 'National Identity Document'. This is a personal identification card that is issued by the Spanish government to every citizen, both Spaniards resident in Spain and in the overseas provinces, and Spanish citizens resident abroad. The DNI is used as proof of identity and personal status. It contains information such as the holder's full name, date of birth, sex, residential address and nationality. It also contains a photograph of the holder. The DNI is not only a physical card but also a digital document that allows online identification and electronic signature.
I need your DNI to verify your identity.
In this this sentence, the speaker asks for the other person's DNI, which is a form of identification in Spain, in order to confirm their identity.
I can use my DNI to book a hotel room.
This sentence suggests that the speaker can use their DNI, a national identification document in Spain, to book a hotel room possibly as a proof of identification.
I lost my DNI and now I need to apply for a new one.
In this sentence, the speaker states that they have lost their DNI and will now need to request a replacement. The DNI here is referring to a Spanish National Identity Card.