Multiple Items for Single Invoice Number

[morristhompson]

Hi. I would like to know how to create Multiple rows(or) Items for Single Invoice which will use Invoice number as unique number. Thanks in advance.

 

[herofox]

you can use thos stert from cell A2

=COUNTIF($C$2:C2,C2)

 

[morristhompson]

Thank you for your help, Mr.herofox.