WoW Forever Names — Reservations Open October 27 For Eligible Upgrades
Early Name Reservation runs October 27–November 3 for eligible upgrades. Full names must be unique across a region; no particular name is guaranteed.
World of Warcraft: Forever's Early Name Reservation runs October 27 through November 3 for eligible upgrade purchases. Blizzard's September 21 naming announcement confirms that reservations are first-come, first-served. Access to the window does not guarantee a particular name.
Forever characters use two names, with the full combination required to be unique within a region. Another player using your preferred first name does not automatically rule it out: a different second name may make the complete name available.

Friends can share a surname if their complete names differ and remain available. Naming restrictions still apply to both parts together, including rules against prohibited wording and impersonation.
The official edition breakdown includes Early Name Reservation in the Skyborne Heroic Pack. The Skyborne Epic Pack includes the Heroic benefits, and the Warcraft Forever Collection includes the Epic benefits, so both also include reservation access. The naming post does not specify an opening hour or timezone.
You can hide the second name in the game world through Options, Nameplates, then the My Secondary Name checkbox. It will still appear in chat. That setting changes the display, not the full name used for regional uniqueness.
Prepare a few complete combinations before October 27 and confirm your upgrade includes reservation access. If the first choice is unavailable or fails the naming rules, you will need another combination.