The BitPay and Copay wallets give you the option to adjust the fee schedule. This isn’t a manual fee that allows you to set the exact amount of satoshis. Instead, the BitPay and Copay wallets use ‘estimatefee’ from Bitcoin Core. As defined by Bitcoin ABC, ‘estimatefee’ sets a fee that should include your transaction in an appropriate number of blocks dependent on the fee schedule you assign.
Setting the fee rate policy only changes the fee for P2P transactions. Any time you pay an invoice through Payment Protocol, the fee is set by the invoice and based on the merchant’s preferences.
To change this follow the below steps:
From the home screen of the wallet, click Settings
Click on Bitcoin network fee policy
There are 5 policies, ranging from Urgent all the way to Super Economy. Urgent will try to include your transaction within the next 2 blocks. Super Economy will try to include your transaction within the next 4 hours. You can see the current satoshis/byte that each fee will use for this transaction, and decide which fee is best for your situation. After you have selected the desired fee, you can click back at the top, and return to the home screen.