Note to As You Like It, 1.2.123-124: "With bills on their necks, 'Be it known unto / all men by these presents'"
With bills on their necks, 'Be it known unto / all men by these presents': —A bill is a placard, and the phrase, 'Be it known unto all men by these presents' was often used in legal documents, meaning "be it known unto all men by this document." Of course Rosalind is punning on Le Beau's use of the word "presence," and I believe that she is mocking Le Beau by saying that the fine young men he is describing were actually common criminals condemned to be pilloried with a "bill" about their crimes, as in the 17th-century woodcut below.
Image source