Short answer: 12,345,678 reads as one crore twenty-three lakh forty-five thousand six hundred seventy-eight in the Indian system and twelve million three hundred forty-five thousand six hundred seventy-eight in the international one.
Why the grouping changes the words
The Indian system inserts a comma after the first three digits and then every two digits (12,34,567), so the same digits land in a different column and therefore get different names. The page prints both groupings next to their words so the correspondence is visible.
Worked example
A cheque for 1,05,000: Indian grouping gives “one lakh five thousand”, so the line reads “Rupees one lakh five thousand only”. The international system would call the same amount one hundred five thousand, which many Indian banks would query.