You'll pick during domain selection which will be in the next few weeks/months.

If a server isn't full you will be able to pick it during domain selections for those with titles\ep to do so.

If you just buy the base game, then later you will pick it I imagine during character creation if not right before\after char selections\creation

And I swear I read somewhere that if a server is marked as full, but you have a Char code to join with. You will still be able to join the server with that char code.

Yeah, I knew about being able to join a full server with a character code I just wasn't sure about the other. I kind of want to play on the EU server even though I live in the U.S. but I was not sure it was possible.

Even people without titles will be able to play within KoE/MuD. So you be most likely able to pick doing land selection.

Nothing stopping you from playing on any server, no matter where you lived. Not locked out, like how some games do it.