Where is the serial number on a Samsung washing machine?

Open the door and look at the front panel near the bottom of the drum opening; the rating plate is also on the rear.

Around the door opening, on the rim of the drum
On the back panel

Source: Samsung UK – How to find the model and serial number of my Samsung product

How old is my Samsung washing machine?

Copy the serial number from the plate, or paste everything on it.

All Samsung appliances