Can I submit a bill to multiple users for approval?

No. A bill should be approved by one particular user. If that user is not available or is not the correct approver against the spcific bill then an Admin can always change the approver by going to ‘Purchases’ > ‘Bills’ and then clicking the approver name against the bill. You can also do this in bulk for multiple bills at the same time by ticking the box next to the bills on the left, then clicking ‘Change Approver’.