I've seen no evidence that there's any presidential power to mandate mask-wearing. Even congressional power - via law that would have to be signed by the president or a veto overturned - is debatable.
Think about it - were there some national power like this, what
couldn't those in power decree, regardless of the intent?
IF there's a power to do this, it would have to be on a state level.
Is a federal mask mandate constitutional?