Hello and welcome!
I have a cute gift set to share using some of Doodlebug Designs new cut files from the Silhouette Online Store, these are from the Here Comes Santa Claus collection. I used a box from the store to create the mailbox gluing the front and a back piece onto it.
For the card I just created an offset of the back layer and welded an offset of the envelope. I did a print n cut for the Merry Christmas. The paper used is from the Here Comes Santa Claus essentials kit and Here Comes Santa Claus petite print assortment.