I am a Real Estate Agent and currently only manage my own rental buildings.  I have 11 units in one building and 4 in a second building and we are growing.  Our books are in QuickBooks Online.  We have the class tracking set up for each building.  Now we are looking to automate billing for rents.  I want to be able to send a bill for their rent automatically, use their checking account with minimum fees to us for the service rather than more costly options with debit or credit cards.  How does QuickBooks recommend we do this?  Is it an emailed invoice to them once a month?  Is it an ACH?  And if it does not get funded by a certain date, can it rebill with a late charge?