Include a Payment Processor filter on the appropriate built in Reports
For most persons the default contribution reports are satisfactory but don't allow you to identify income by payment processor.
See: https://civicrm.stackexchange.com/questions/27695/report-with-payment-processor https://civicrm.stackexchange.com/questions/21990/can-we-report-on-contributions-by-payment-processor
One possible solution is to install Extended Reports but for those who prefer not to have any extensions running this can be restrictive.