Default invoice numbers start at the number 101.  

To set a custom invoice number pattern, please visit Settings/Tools/Reports->Invoice/General Settings option.  Custom invoice number includes three parts. A prefix, a suffix and a starting number.  Prefix and Suffix can be any string without quotation marks. (e.g., DLAW). Starting number must be a numeric.  

For prefix or suffix, you may enter the word  YEAR and system will automatically use four letter year (e.g., 2013)  of invoice year.  For example, entering prefix YEAR-  will generate invoice number 2014- for all invoices created in year 2014.

Please note that any changes in custom numbering and pattern will apply to all invoice, past and future.

In addition, you can also change invoice numbers of individual invoices to any custom word or number or a mix thereof. Simply click on the invoice number in the listing of invoices and enter a custom number/word.