an envelope with a layer of bubble wrap (= a sheet of plastic bubbles) inside, used especially for sending things that can be easily damaged

Put the whole thing in a padded envelope and send it off. 将其全部放进软垫信封里寄出。

Instead of shipping small items in boxes, use padded envelopes when possible. 如果可以的话，用软垫信封而非纸盒邮寄小型物品。