Requests for unnecessary personal data or security codes

To buy or sell an instrument you should never give the other person:

passwords;
one-time passwords (OTPs);
PINs;
CVV/CVC codes;
recovery codes;
online banking credentials;
copies of identity documents unless an official, verified process genuinely requires them.

If a legitimate service requires sensitive information, enter it directly in the official app or website, never in a chat with the other party.