I will link some other threads that have the information you require that I got by typing "Name Reservation" into the search function, please try searching before creating a new post as more often than not you will find that your question has already been answered over the years of development.
I will now go ahead and close this thread for being a duplicate post.
https://www.pantheonmmo.com/content/forums/topic/2949/early-name-reservation
https://www.pantheonmmo.com/content/forums/topic/3602/early-name-reservation
https://www.pantheonmmo.com/content/forums/topic/3621/early-name-reservation
https://www.pantheonmmo.com/content/forums/topic/4476/early-name-reservation
(All separate posts with the exact same title...)