Customise reference number

Is there a way to automatically customize reference number?

Take this as example in sales invoice

Normally sales invoice will auto generate every time we make.

I want like this


INV = sales invoice
2018 = years
09= month
001 = indicates that the number invoice that have been made for this month

Hope someone reply


All sequences are purely numeric. But you can manually enter a number at the first of every month and let Manager take it from there. For example, on September 1, edit your first invoice to be 201809001 and the following one will be 201809002. Then, on October 1, edit the first invoice to be 201810001.