Usually on one of the side walls, even where the crisper drawers are. On older units it can even be on the bottom rail at the kickplate area.

Manufacturers used many locations, side panel lower front corner, under the lid somewhere, on or behind the front loader door and even on the top backside lip of the backsplash.

Usually on the back side of the door or the frame area behind the door, the top backside lip of the backsplash.

Normally somewhere on the edge of the door or frame, somewhere where water normally won't destroy it.

Behind the drawer front on the frame area. Sometimes on the frame behind the oven door and even under the cooktop beneath the coil elements. This is also the case with Gas Ranges.

Uprights are the same as Refrigerators but Chest Freezers are usually on outside on an end near the control or even on the back somewhere.

Counter Top units can be virtually anywhere including the back but O-T-R units will never have it on the backside.

Normally on a sticker up underneath but most times these tags are very tough to read due to cooking all the time beneath them.