Fondants have many meanings

Fondant as in Icing
Fondant as in Chocolate fondant deserts
Or Marzipan Fondants lol.
If icing, do not put in the fridge. Wrap in clingfilm, then in a bag, then in a air tight container. If you have trex, smear a very light amount on the fondant so it does not dry out.
Now if its Fondants as in the Dessert, you can put them in the freezer and cook from frozen, just add 5 more minutes cooking time

Was a pastry chef for many years in a hotel, and we would freeze them

Gordon Ramsey too says ok to freeze.
Jax