Payment Gateway Detail is the edit page opened from Payment Gateways. The fields change to match the provider you selected.Depending on the gateway, you may need to enter API keys, client credentials, account identifiers, bank details, or an email address. Many gateways also have a test or sandbox mode.
Use test credentials while testing and keep live credentials private. Make a test payment before enabling a new gateway for customers. If you change an existing gateway, check that its current credentials have not been replaced accidentally.