- ID: Unique identifier for the user.
- user_login: The user's login name.
- user_pass: The user's password (hashed).
- user_nicename: The URL-friendly user name.
- user_email: The user's email address.
- user_url: The user's website URL.
- user_registered: The date and time when the user registered.
- user_activation_key: Activation key for the user.
- user_status: The status of the user.
- display_name: The display name of the user.
- roles: Array of the user's roles.
- cap_key: Capability key.
- caps: Array of the user's capabilities.
- allcaps: Array of all capabilities the user has, including inherited ones.
- filter: Filter context applied on data.
- get_userdata(): Retrieves the userdata of a user by ID.
- get_user_by(): Retrieves user data given a field and value.
- wp_insert_user(): Inserts or updates a user in the database.
- wp_update_user(): Updates a user's data.
- wp_delete_user(): Deletes a user from the database.
- wp_create_user(): Creates a new user with a specified role.
- wp_set_password(): Sets the password for a user.
- get_user_meta(): Retrieves a user's metadata.
- add_user_meta(): Adds metadata for a user.
- update_user_meta(): Updates a user's metadata.
- delete_user_meta(): Deletes a user's metadata.
- is_user_logged_in(): Checks if the current visitor is a logged-in user.
- current_user_can(): Checks if the current user has a specific capability.
- get_current_user_id(): Retrieves the ID of the current user.
- wp_get_current_user(): Retrieves the current user's data.
- user_can(): Checks if a user has a specific capability.