I need user ID to be same as Username

I need a way to have my external plugin to read each of my users as their username. At the moment it seems like it is only reading them as their user ID.

I would like to have the user id to be the same as the username. I found this resource but I'm not sure if it is what I am looking for (based on the info above) or even how to implement it.

Please let me know if you have any ideas how to make user id same as username.

Kindly,

Paul