Network or gas fees occur every time transaction is executed on a blockchain. They are transaction fees that are paid to cryptocurrency miners by whoever is executing the transaction.
Important: the network or gas fee is not a fee applied by BVNK but rather by the blockchain.
Check out this example below from an Ethereum transaction on MetaMask:
For more information, check out the gas fees FAQs from MetaMask.
You can also check the Ethereum documentation on Gas and Fees.