Whether you are making Spot Gloss, Raised Spot Gloss, or Gold Foil Cards two files are required.
One for the ink which we call the Design Layer. This is a standard file that you would use to print other products, and has the same requirements.
The second file tells us where to put the Special Finishes you chose. This will be a black and white file, like a chess board. The black in the file is where the Element will be applied.
Here's an example for Gold Foil:
Design Layer (Ink)
Element Layer (Foil or Spot Gloss)
We want to use vector artwork for this layer because low quality artwork can make the Foil or Gloss come out jagged