Why should I check my personal account on my smartphone? Are verification codes and signatures secure?

When using smart phones to query personal accounts, security measures such as verification code and signature are common authentication methods to ensure that only authorized users can access and operate accounts. Verification code is a one-time verification code generated by SMS or mobile phone application, which is used to confirm the identity of users. Signature is the user's signature on the mobile phone screen, which is used for authentication. They provide additional security to ensure that only the real account holder can access and operate the account.