Hello, I too have a friend code that is up for use. This code will unlock exclusive items that are only obtainable through this process.
To input the code, go to Mog Station, you must register your service account and subscribe to the game, then click on "friend recruitment code" to enter your code.

Code:
UPQHUPGC

If you need any help around the game, find me on Sargatanas and I'll be glad to assist.
Thank you~