QuickBooks does not delete it only inactivates, so when you inactivate it disappears from your view and does not count for your subscription limits.  We have all added a vendor or customer in error.  If I have no data for the vendor or customer, I change the name to zz DELETE 03-31-2021.  The date changes so it's unique each day.  If I have more than one I just add (2), (3), etc.  This gives it a unique name and sorts to the bottom of the list if I want to look at inactive vendors at some point.  If you don't change the name, if you ever try to add the vendor in the future, it will give you an error and tell you, you already have a vendor with that name.