How is At Will spells intended too work?

@JeremyECrawford how is 'at will' spells intended too work? Can it be cast with out spending an action or bonus action?

— Nash.dewar (@DewarNash) November 2, 2015

A spell requires its normal casting time, even if you can cast it at will. #DnD https://t.co/G4ipCJgOrN

— Jeremy Crawford (@JeremyECrawford) November 2, 2015