How to define user in discord.js?

@haylee.mertz 

In discord.js, a user can be defined as a member of a Discord server who interacts with the bot through commands, messages, and other interactions. Users can have various properties and methods associated with them, such as their username, discriminator, ID, avatar, roles, and more. They can be referenced and interacted with in different ways, such as sending messages, fetching user information, and managing user permissions.