Hi @Lindapo
The closest you'll get in QBO is...

but this will obviously fail for invoices raised on the 1st day of a 31 day month & any day in January (because February doesn't have 30 days). There are probably others - but it's been a long day!
You will just have to get used to manually editing the Due Date on each invoice (sorry!).
If you tab to the Due Date box & use the h keyboard shortcut (as in "month"), it'll soon become second nature.
Hope this helps.