What are coins?
Pokémon Masters Guide
Coins are an in-game currency that you can use to purchase different items from the store. You can get them from a variety of sources such as completing stories, of finishing some courses. You can also gain coins from selling items such as pearls.
Whenever you finish a battle, you should see the amount of coins that are awarded to you through the rewards screen through the "Coins Earned" section.
What are coins used for?
You can use coins to exchange for helpful items to improve your Sync Pairs. If you open the shop and check exchange, you can use coins for the following:
Evolution Shards
Evolution Crystals
Move Gauge Slots
These are useful if you want to evolve a Pokemon, or perhaps increase the amount of moves that you can use in a battle.
Where can I get more coins?
There are different methods of getting coins in the game. You can do any of the following:
Complete Story Quests
Complete Training Courses
Complete Coin Supercourses under Training
Sell Pearls
Complete Fieldwork (Chapter 3 Fieldwork provides a Pokeball that contains 10,000 coins)
The Coin Supercourses are great for getting coins fast since they provide both coins and pearls that you can sell. The higher difficulty that you can clear, the more coins that you can possible get.