Hi h.barnsley,
Welcome to Community! Having the option to create bills currently isn't available in the mobile app. I can see how the option to use this feature would be a great addition, and I encourage you to submit a suggestion to our Development Team. In the interim, you can sign into your QuickBooks Online account from a web browser, to successfully enter your supplier bills.
Please reach out again, if you have other questions. We would be happy to help!
