In PHP radius ISP can set there default configuration Like ISP information, ISP logo, set Currency, Billing Title, Billing Terms, Billing TAX. Portal Setting etc.
to open an ISP Portal Configuration on sidebar > Config Admin Config option.that will display different tabs on a page.
On sidebar menu click on Config > Admin Config option.
Click on the billing setting tab.
View Printing Setting in invoice title and invoice terms option, now change the information as you want.