Teferi's Realm — ruling 1

This has the supertype world. When a world permanent enters, any world permanents that were already on the battlefield are put into their owners' graveyards. This is a state-based action called the "world rule." The new world permanent stays on the battlefield. If two world permanents enter at the same time, they're both put into their owners' graveyards.

Teferi's Realm — ruling 2

Can affect itself if you choose "non-Aura enchantment".

Teferi's Realm — ruling 3

Does not affect token permanents, only cards.

Teferi's Realm : règles, fonctionnement et interactions (MTG)

Teferi's Realm is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

At the beginning of each player's upkeep, that player chooses artifact, creature, land, or non-Aura enchantment. All nontoken permanents of that type phase out. (While they're phased out, they're treated as though they don't exist. Each one phases in before its controller untaps during their next untap step.)

How it works : Teferi's Realm

Original English text — Wizards of the Coast / Scryfall

#1October 1, 2008· Wizards of the Coast
This has the supertype world. When a world permanent enters, any world permanents that were already on the battlefield are put into their owners' graveyards. This is a state-based action called the "world rule." The new world permanent stays on the battlefield. If two world permanents enter at the same time, they're both put into their owners' graveyards.
No other card is named in this ruling.
#2August 1, 2005· Wizards of the Coast
Can affect itself if you choose "non-Aura enchantment".
No other card is named in this ruling.
#3October 4, 2004· Wizards of the Coast
Does not affect token permanents, only cards.
No other card is named in this ruling.