To add payment terms click on Edit Terms or press (t). When clicked on Edit Terms a popup will open. In which the payment terms details are added and then confirmed.
Click on Edit Terms in Payment Terms section and fill payment mode, credit days, advance %, payment terms description.
For payment mode the mode can be typed or can be selected by Shift + * command.
If the payment mode is not present or it is a new mode then click on the + icon for getting category quick edit screen where a user can type its name, nick name group code all in one screen and can add a mode quickly.