In Spanish, the phrase ‘do you know’ is translated as ‘¿sabes?’. This is the informal form used when speaking to someone you know well, such as a friend or family member.
If you want to use a more formal version, for instance when addressing someone you don’t know well or speaking to an elder, you would say ‘¿sabe usted?’. The difference lies in the use of ‘tú’ (informal ‘you’) versus ‘usted’ (formal ‘you’).
For example, if you want to ask your friend if he knows the answer to a question, you would say, ‘¿Sabes la respuesta?’ On the other hand, if you’re speaking to a professor in a classroom, you would ask, ‘¿Sabe usted la respuesta?’