Magus of the Will

• WWizards of the Coast2020-08-07
  Official Ruling
  Magus of the Will doesn't change when you can play the cards in your graveyard. For example, if you have a creature card without flash in your graveyard, you can cast it only during your main phase while the stack is empty.
• WWizards of the Coast2020-08-07
  Official Ruling
  You pay the costs for a card in your graveyard if you cast it. You may pay alternative costs such as overload rather than the card's mana cost.
• WWizards of the Coast2020-08-07
  Official Ruling
  You may play a land card from your graveyard only if you have an available land play.
• WWizards of the Coast2020-08-07
  Official Ruling
  Cards that would be put into your graveyard are exiled even if you didn't play them this turn, such as a nontoken creature that would die.
• WWizards of the Coast2020-08-07
  Official Ruling
  Tokens are put into your graveyard as normal (and cease to exist soon after). Abilities that trigger when a creature dies can trigger on token creatures being put into your graveyard but won't trigger on nontoken creatures being exiled instead of being put into your graveyard.
• WWizards of the Coast2020-08-07
  Official Ruling
  If another effect tries to change where a spell is put as it resolves, such as that of a rebound or buyback ability, you may choose whether to exile the card to Magus of the Will's effect or to apply the other effect.

Rulings via Scryfall