In BloFin, you'll only pay a fee when you do an on-chain withdrawal transaction. The fee charged is called Gas Fee, which is used to pay miners as a reward.
You can see the fee amount on the Withdrawal page when you are withdrawing
How do I calculate how much I will receive when I withdraw my currency?
The system will calculate the fee automatically. The actual amount that will be credited to your account on the withdrawal page is calculated with this formula: The actual amount in your account = Withdrawal amount – Withdrawal fee
Note: The handling fee is fixed and has nothing to do with the amount you withdraw.