Will under work surface fridge & freezer stack?

[breatheslowly]

Wer are moving and there is only space if we stack them, but I am not sure if they are designed to do this.

Ask the manufacturer(or manufacturers) of the items. You can find their details via the websites of the items.

You can buy stacking kits for washing machines and tumble driers, however both are much lighter than fridges & freezers ...
Not sure it would work TBH