how to replace “INVOICE” opposite to the logo with a different text

i saw this reply on a previous topic. but my question is where and how do i add the add

add_filter(‘getpaid_invoice_type_label’,’_my_invoice_label’,10,2); function _my_invoice_label($label,$invoice){ if($label==’Invoice’){ $label = “Tax Invoice”; } return $label }

Hello,

That is a PHP code snippet, and you can add it with a code snippet plugin.

https://woodysnippet.com/