I just want to change heading from invoice to tax invoice

Dear sir
I am using manager from long time but now as per UAE law we must have to put heading on invoice TAX INVOICE so please guide me how i can change the heading feom invoice to TAX INVOICE it will be very helpful for me if someone guide me.

Thanks

See

in particular, Custom Title option checked on invoice
For which see
Sales Invoices: Create sales invoices

Hello Subhani,

If you need any help on Invoice, Quote, or any form customization, you can contact me,