What additional feature can enhance email security?

Enabling two-factor authentication (2FA) significantly enhances email security by adding an extra layer of protection beyond just a password. When 2FA is implemented, the user must provide a second form of verification, which could be a code sent to their mobile device, an authentication app, or a fingerprint. This requirement ensures that even if someone manages to obtain the user's password, they would still need the second factor to gain access to the account. This greatly reduces the likelihood of unauthorized access and helps protect sensitive information contained in emails from being compromised.

In contrast, utilizing plain text for all messages does not contribute to security, as it does not encrypt the content, making it easier for eavesdroppers to read. Adjusting the font size of emails is unrelated to security and does not protect against any potential threats. Sending messages at odd hours may have no effect on security and could potentially raise suspicions, but it does not improve the safeguarding of the email content or the account. Therefore, two-factor authentication stands out as a crucial enhancement for preventing unauthorized access and ensuring email integrity.