When Oath of Teferi enters, exile another target permanent you control. Return it to the battlefield under its owner's control at the beginning of the next end step. You may activate the loyalty abilities of planeswalkers you control twice each turn rather than only once.

Trample, haste If you would put one or more counters on a permanent or player, put twice that many of each of those kinds of counters on that permanent or player instead. If an opponent would put one or more counters on a permanent or player, they put half that many of each of those kinds of counters on that permanent or player instead, rounded down.

At the beginning of your end step, if you didn't activate a loyalty ability of a planeswalker this turn, you lose 2 life. {4}, {T}: For each planeswalker you control, you may activate one of its loyalty abilities once this turn as though none of its loyalty abilities have been activated this turn.

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead. If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.