Activate "Detail" User Define on Sales Invoice

Below are guideline(s) to activate detail user define on Sales Invoice screen :

Step 1 : Go to System >> Administrator Menu >> User Define Caption >> Individual Screen Setting

Choose "Sales Invoice" >> tick "Transaction Detail User Define" (It depends on how much you would like to add) >> change the user define caption >> tick "Save Individual Screen Setting"

Step 2 : Sales >> Sales Invoice >> Detail