A verification code is designed to prove that you control an account or device. If you gave one to someone else, assume they may have used it.
Secure the affected account from a device you trust. Change the password, review signed-in devices and sessions, and check recovery email addresses and phone numbers.
If the code was related to banking, payments, a SIM change, or account recovery, contact the relevant provider through its official app, website, or trusted contact number.
Do not give the person another code because they claim they need it to reverse, cancel, or secure what happened.