/u/waritter gave a very comprehensive answer for a similar question. I'd also add that some records exist for "armored archers," distinguished in the records from the regular archers. What exactly qualified them as "armored" is unknown, as no sources explicitly define a difference between standard and "armored" archers. Were the clerks trying to differentiate men wearing brigandines from men wearing jacks? Does it mean leg or arm protection or perhaps better helmets? We can't say exactly, but given that we do know that archers could often expect to move up into the ranks of men-at-arms, it's possible that the "armored archers" were archers who had acquired bits and pieces of better gear in the hopes of being promoted.