The Linking Cord triggers the Evolution of certain Pokémon (all of which can alternatively evolve when traded) upon use. This consumes the Linking Cord.
As of version 1.0.13, if the Linking Cord is used from the Bag, it will reward the player with 5 candies of a random Pokémon that evolves using the Linking Cord.
While the Linking Cord is used to evolve Pokémon that evolve when traded, it cannot be used to evolve Pokémon that evolve when traded while holding an item; instead, in Pokémon Legends: Arceus, those Pokémon evolve simply by using that item on them.
The sprite of the Linking Cord in Pokémon Legends: Arceus takes influence from a form of Japanese knot tying called Mizuhiki. The knot in particular is an Awaji knot, which is used to represent togetherness — a possible nod to the Link Cable's original use.