Two-step verification is an enhanced security feature that is designed to prevent someone else from signing into your Samsung Account.
It can strengthen the security of your account by using two different authentication factors to verify your credentials; a password and an extra security code.
When signing into your Samsung Account you will enter your password and shortly after then receive a verification code to your mobile phone via text message. If someone attempts to sign into your account with your password, they will not be able to access your account due to not receiving the additional verification code.
To learn more about the two-step verification process please view further information here.