When Oath of Teferi enters,
exileTo exile an object, move it to the exile zone from wherever it is. See rule 406, “Exile.” (CR 701.13) 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
activateTo activate an activated ability is to put it onto the stack and pay its costs, so that it will eventually resolve and have its effect. Only an object’s controller (or its owner, if it doesn’t have a controller) can activate its activated ability unless the object specifically says otherwise. A player may activate an ability if they have priority. See rule 602, “Activating Activated Abilities.” (CR 701.2) the loyalty abilities of planeswalkers you control twice each turn rather than only once.