1) Armored 2) Armoured 3) Dropped in the post 4) Fedexed 5) Like many thank you cards 6) Like Sir Galahad on a quest 7) Mail-clad 8) On its way 9) Popped in the post 10) Posted 11) Sent 12) Sent a letter 13) Sent by Canada Post 14) Sent in 15) Sent in a stamped envelope 16) Sent off 17) Stamped and sent Found on https://www.crosswordclues.com/clue/mailed