The User ID Component is for controlling content visibility based on a user’s ID.
Here you select whether the current user’s ID should be equal to or not equal to the selected user IDs.
B) User Name & Email
Here you select the user based on their user name and email.
C) User ID
Here you can see the ID of the selected user.
What are User IDs?
WordPress assigns each registered user of your website a unique user ID. Unlike a user’s name, email, and other personal information, a user’s ID cannot be changed.