Alter Writing

You alter the contents of a piece of writing, such as a map, journal, newspaper, or letter, to your likings. You do not need to see the contents of the target in order to alter it. You could make the words illegible and scrambled, or you could make it so that the contents of the target are written to your likings. A creature can make an Intelligence (Arcana) check against your spell save DC to discern that the message has been tampered with, after which the spell ends.

You can expend a spell slot of 1st level or higher to extend this spell's duration by an additional 24 hours, so long as you're on the same plane of existence as the altered message.