In order to provide a number to each document issued, you can create Numerators 

(Settings - Document Numerators -Add Numerator)

Every type of document has to be linked with a numerator. The same numeration can apply to various document types. 

You can manually reset to zero each numerator to start a new numeration (at the beginning of a new season or tax year for example).

Each numerator requires:

  • Name: Name of the Numerator (e.g. Invoice, Receipt)
  • Format: Format of the Numerator. It can include "Number" and "Sequence". These values will be replaced by the corresponding number of the numeration and the year when the document was issued. 
  • Sequence name: sequence name of the numerator, e.g.: 2016 (year).

Click on Edit 

and then Reset to Zero to start a new numeration