Hi RP09,
Currently, printing a bill is unavailable in QuickBooks Online (QBO). As a work around you can click on the short cut keys CTRL + P to print the bill.
I can see how having the option to print bills in QuickBooks Online would be helpful. I'll do my part and pass this suggestion along the Product Development Team once more. The more attention that is brought to this subject, the more likely there will be change.
I would recommend also sending your product feedback in your QBO account through the Settings icon > click on Feedback.
Please know that I'm just a post away if you have more questions or concerns regarding the features in the Online version.