Hi nicolelewisrmt-g,
Welcome to Community! The QuickBooks Online mobile app is a dynamic way to accomplish your bookkeeping goals while on-the-go. However, there are some limitations, in keeping your data secure. To ensure you're able to enter the required elements for adding payment methods and terms for your customers, I recommend logging into your QuickBooks account on a web browser.
If you have any other questions, please don't hesitate to reach back out. We're always happy to help!