I am new to using fondant and wanted to know how to store a cake covered in it. I was told not to refrigerate it. What do you do if the filling needs to be refrigerated? Thank you

Then you will have to refrigerate it. The problem with refrigerating fondant covered cakes is that they sweat when they are taken out of the fridge. Just make sure you leave yourself enough time for it to dry before delivering it, so that it can be pretty again.

Thank you for the advice. Does the sweat affect the look of the fondant after it drys (spots, streaks) and would it make any fondant decorations fall off?

After you take it out of the fridge, don't touch it at all, don't try to mop up the condensation, don't do anything, and it should be fine.

If you touch it, then it will look funny.

When you say "Just make sure you leave yourself enough time for it to dry before delivering it, so that it can be pretty again" -- How much time do you need to give? This time it's out of the frig will add onto the time it's at the wedding site. Won't the fillings that require refrigeration be pushing the time limits then?

I find with a large cake, it can take an hour or two to dry, depending on the humidity levels that day. I normally just explain about the condensation and tell the person I made the cake for not to touch it until it dries.