Assigning specific roles tailored to customers isn't possible in the QuickBooks Online (QBO) mobile app, Steve378. However, I know of an alternative that can help you achieve your goal.
You can still assign specific customer roles by logging into your QBO account through supported browsers. Roles such as Bookkeeper, Accounts Receivable Manager, and Standard Limited Customers and Vendors can be effectively managed in this way to enhance your experience while working with QBO.
For detailed information, check out this article: User roles and access rights in QuickBooks Online and Intuit Enterprise Suite.
Moreover, to monitor the activities of your users, you can track their actions in the Audit Log. This log provides a detailed record of who made changes to your accounts and specifies the nature of those changes.
I'm here to assist you with managing roles whenever you need further support. Feel free to visit this forum anytime, and I'll ensure that everything runs smoothly for you.