Hi yakker,
It's great you're taking advantage of the Bill feature in QuickBooks Online to easily track your expenses. Knowing every functionality we offer helps you make the best out of your business. I'll be happy to share more on this.
At the moment, there's no feature available to set up reminders for upcoming bills. I can see how having this option could have benefited your business, and I encourage you to submit feedback directly to our engineers to share your thoughts on this. We are always looking for new ideas in innovating the product, and your opinion helps a lot with that.
I also invite you to visit our Apps menu to explore any third-party apps that could better assist you with your task.
Don't hesitate if you have any other questions.