Aditya Shah

You can display a user ID of any user on his profile page or anywhere you want with a simple shortcode or a php code. 
You can use the shortcode: “[user-id]” or php code “echo do_shortcode(“[user-id]”);”

User ID

This is a WordPress plugin which displays user id with a simple shortcode or PHP code.

shawfactor

LH Add ID Columns adds functionality that should be in core. Namely displaying columns listing the user and post ID’s on the appropriate admin screens in wp-admin. All such columns are sortbale.
This is extremely useful when you are needing to work with posts and users both in the backend and in the database.

LH Add ID Columns

LH Add ID Columns adds user and post ID's to the WordPress user, post, page, and custom post type listings.

User ID vs LH Add ID Columns