To access your payment policy navigate to Contracts within your project. Scroll down until you find Payment Policy and select change in the upper right-hand corner of the box.
If you want to use a previously created payment policy, select it from the drop-down menu. If you want to add a payment policy, select Create payment policy.
You can now edit the:
Full Payment Due Date
Processing Fee settings
These changes will also be reflecting in the Billing section of the contract.