I love the contents! As far as I can read, the parcel consisted of a 'box' weighing 2,3 kg simply containing 'kjeks', meaning biscuits! The shipping cost of almost 10 kroner was a significant amount at that time (26 March 1957?) - so it seems to me someone was desperate for biscuits from Notodden !

. Maybe homemade biscuits sent from a mother (Anna) to her daughter (Inga)?
Interestingly, the parcel note was first postmarked upon departure Notodden (26?) and then at customs office in Oslo (27?).
(Btw - Tim is correct, 'Tollangivelse' is a custom declaration)