https://wccftech.com/wow-classic-name-reservation/

Blizzard has announced that WoW Classic name reservation will open up next week on August 12 at 22:00 GMT / August 13 at 00:00 CEST.

Ahead of Classic’s release at the end of this month, players with an active World of Warcraft subscription or game time will be able to create up to three characters per account and have the names reserved. Once released, players will be able to create a maximum of 10 characters per Classic realm and a maximum of 50 characters across all realms in a region. As expected, there can only be one faction per realm on PvP realms.