When you add funds to your campaign wallet, a 2.9% payment-processing fee applies and is grossed up into the charge: so funding $1,000 charges $1,029.87 and puts the full $1,000 in your wallet.
This is the only brand-side fee on money movement: when creators are paid from your wallet, no extra platform fee is added on top.
The fee appears as part of the same card charge, not a separate line on your statement.