An admin fee is a fee that is separate from the swap fee and is paid to veCRV holders. The swap fee is a fee that is paid to the liquidity provider (LP) for providing liquidity to the pool. This fee is generally .04% for stable pools and can be up to .4% for crypto pools. The admin fee is paid out of the swap fee and goes to veCRV holders. This fee is used to incentivize veCRV holders to provide liquidity to the pool. The admin fee is also used to cover the costs of running the pool, such as development and maintenance. By paying veCRV holders an admin fee, it encourages them to provide liquidity to the pool, which helps to keep the pool liquid and makes it easier to trade.
Swap fee. Generally stable pools it's .04%, 3pool less. Crypto pools, the swap fee dynamic, and changes based on the price of the assets in the pool (Generally a max of .4% for crypto pool). Half of these fees go to LP's, the other half, known as the admin fee, goes to veCRV holders