Allow listing is a security technique that allows only specific IP addresses or domains to access a network or a service. By adding the office IP address as an exception, the company can prevent two-factor authentication from being triggered when users are connected to the office Wi-Fi, since the office network is considered trusted. This way, users will only be prompted for two-factor authentication when working outside of the office, which enhances security.
References: The following web search results provide more information about allow listing and two-factor authentication:
What Is Two-Factor Authentication (2FA)? | Microsoft Security: This article explains the concept of two-factor authentication, its benefits, and its methods.
Change your two-step verification method and settings - Microsoft Support: This article shows how to manage your security verification methods and settings for your work or school account, including how to turn on two-factor verification prompts on a trusted device.
2FA Directory: This website lists all the sites that support two-factor authentication, and the methods they use.