I am confused.  Why would you like to do this?  Normally as a customer, we do not dictate the vendor's numbering sequence.  The program is designed based on this concept so there is no way to auto increment the vendor invoice number in in the payables module.

If you are creating invoices to pay suppliers what you owe them, you can use an invoice number like Apr/19, May/19 etc. if you pay once a month or just tell them what you owe and have them send you an invoice.

If a vendor is making a purchase why can't the invoice be the next number in line 

Vendor A 2009 next vendor purchase is 2010 and so on ?

Am I missing something ?

Btw . Thank you for replying to me . Greatly appreciated 

Steven 

I'm not sure if you are missing something or if I am.

Vendor = people or companies you buy from

Customer = people or companies you sell to

If a vendor is buying from you, they are your customer, not your vendor.  And your customer invoices do auto increment if you leave the setup of your company file with the default settings.  The numbers do not increment per customer, but for all customers.

If you are buying from a company, you are buying from your vendor but you are their customer.

Are you really talking about vendors and your purchases (Money Out of your business) or customers and your sales (Money In to your business).