Hi @ThumbelinaPM,

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.