Previous Apple TVs had a solution in the form of the Remote app,
which let you use your iPhone’s virtual keyboard to enter any text
you might need to type. Unfortunately, that app has yet to see an
update that supports the fourth-generation Apple TV.
Nor can the new Apple TV connect to a Bluetooth keyboard — it
just doesn’t show up in the Bluetooth menu — so you are, as of
now, completely confined to one-letter-at-a-time text entry.
I don’t really need to say it, but I’m going to: Apple, this
sucks. It’s so easy to set up the Apple TV with an iPhone; why
can’t there be an option for all password prompts bounce over to a
nearby unlocked iOS device? Or, barring that — give us an update
to Remote app. Or a Bluetooth keyboard. This is painful.
It’s also pretty frustrating that you can only log into one Game Center account at a time. That seems downright wrong for a shared family device. I can only guess that a lot these seemingly obvious things are just the usual low-hanging fruit that doesn’t make it in to a 1.0 release.