Thank you for coming to the Community for help, @ljstrangpartners.
Adding bills using a mobile app in QuickBooks Online is currently unavailable. At this time, you can only use the Expense feature to record the bills in the mobile app.
To do this task, you can use the web version of QBO. Simply open a browser like Google Chrome, Internet Explorer, or Mozilla Firefox and log in to your QBO account. For detailed steps, see the Enter bills section through this article: How to enter and pay bills.
Mobile app features differ from one kind of phone model to another. You can open this article to see which model has which feature available: Compare mobile app features.
Please feel free to drop your questions below. I'll make sure to get back to you. Have a good day!
I'm new to Quickbooks and had expected to be using the mobile app, on the go including being able to add bills. I just dont understand why that functionality isn't available in the app. Any idea when it might be?
There isn't an announced date as to when this feature will become available in the mobile app.
A workaround I can suggest if you only have access to your mobile device is to log in to your QuickBooks Online company and open your device's browser. This way, you can create bills while still using your device.
To keep tabs with updates released for QBO, you can regularly visit this page: The QuickBooks Blog.
Don't hesitate to drop a comment below, in case you have other queries. I'll be around to help.