Trainers are trying to evolve Kadabra in Pokemon Legends: Arceus.
Pokemon can evolve in multiple ways. You can evolve Pokemon by leveling them up, while other Pokemon may need increased friendship levels or specific items to be used on them. In Pokemon Legends: Arceus, it's an easily accessible process to evolve your Pokemon. It can be difficult, though, to navigate what a certain Pokemon needs in order to proceed with this process. Different Pokemon require various techniques in order to evolve.
Here's how to evolve Kadabra into Alakazam in Pokemon Legends: Arceus.
How to Evolve Kadabra in Pokemon Legends: Arceus
Linking Cords are also used on various other Pokemon to aid in evolution, specifically Machoke, Haunter, and Graveler. This item does not require you to have a specific friendship or Pokemon level. To use it, you just select the item and equip it to the applicable Pokemon that you'd like to evolve.
You can gain a Linking Cord through a request and it is also available for purchase at the Trading Post in Jubilife Village. You will need to use Merit Points to acquire a Linking Cord, which can be obtained by finding lost satchels and turning them in.
Linking Cords are essential if you want to evolve a Kadabra, Machoke, Haunter, or Graveler into their final evolutions.