You need the model and the 12 digit service number, which is displayed on a sticker or data plate, usually at the side/back of the appliance, or on the inside of the door (around the frame).
Here's What you should See
Your model number may be a combination of letters and numbers and could also include characters such as a dash (-) or a slash (/). The service number will consist of 12 digits starting with the numbers "85".