Silver is found in natural ores in mountains, sometimes together with copper ore. the mountain regions of the Winter Wall and the Thauros Spine have some known scattered deposits of silver ore.
Silver is commonly used in decorative items, such as fine cutlery, jewellery, chandeliers, and as luxury versions of practically all items that can be made of silver and still be usable. It's quite common to have at least one silver item in the house for almost all social classes, and these items are often inherited from one generation to another.
All nations on Shireon have their own silver coin in their currency.
The Silver Dagger have a lot of gear made out of silver to use in their werewolf hunting.
Silver and Lycanthropes
It's widely known that Lycanthropes can't stand silver. The details are shrouded in legends and superstitions, making what's true and what's not a bit hard to discern. However, in the book called Werewolves - A Lorebook about Lycanthropy it is said that the silver needs to pierce the lycanthrope's skin, and that it seems that it can't change shape if it has silver in the body.
If a silver item is no longer in use due to being broken or unneeded it can be melted down and recast as a new object. This can be done over and over again, meaning that silver can be used several times for different purposes.
Trade and Market
Silver is an expensive metal, yet it isn't too hard to get. A lot of merchants dealing with decorative items has some silverware on sale, and practically all jewellers make and sell silver jewellery.