Claus. In the letter, they (usually) write about the gifts.
Santa's many letters, and he can not cope alone. So he has helpers, the Elves. They help Santa Claus to pack and send gifts. At night, the children put biscuits and pour milk for Santa. Night Santa Claus arrives on a sleigh with reindeer. Climbs through the pipe into the house, drinking milk, eating biscuits and under the tree leaves gifts.