How do I use Bill Pay in the mobile app? Log in to your mobile app and select the “Payments” tab. If you are unable to see this tab, you will need to sign up for Bill Payer on your personal computer. Have more questions? Submit a request 0 Comments Article is closed for comments. Related articles What is 3Rivers routing number? How do I pay a 3Rivers loan/credit card/mortgage/line of credit? What number do I call if I have a question or problem with my online bill payer? Where do I send Mastercard credit card payments? What does the app look like in the app store?