I was wondering if anyone knows where to buy or how to make silver to put on cake and cake pop. Are there silver candy writters in tubes?
I've never seen silver candy writers. Generally, adding edible silver dust to chocolate or icing yields just grey.
If the silver will--or is likely-- to be eaten, then the product used MUST be edible. The product can't be just "non-toxic" and, if you're in the US, it cannot contain real metal [like dusts that use E numbers to show ingredients contain, E174 is silver]. No real metals, neither silver or gold [E175], are approved for use on food in the US. The FDA considers adding unapproved additives to food grounds for an agency enforcement action.
You can make edible paint by mixing edible silver luster dust with a clear alcohol like vodka, gin, or Everclear, or with lemon oil or extract. On chocolate, this type of paint can bead up, so adding a small amount of edible confectioners glaze helps a lot.