Hello @Anu,
Well actually to convert the numbers into the billions I had put 3 commas and a full stop as a decimal separator. For converting them into millions use only 2 commas and for thousands use only a single comma.
I’m providing a screenshot below of the results that I’ve mentioned.
I’m also providing a link that I used as an reference that provides an explanation about formatting the numbers (although they’re used in the Excel) but same concept was applied here as well). The only thing is they’ve applied it directly under the Formatting tab in Excel so they’ve included words under the quotes and have excluded 0 and commas from it.
Lastly, also attaching the PBIX file of the working as well as providing a link below of the similar type of query asked onto the Power BI Community Forum.
Hoping you find this useful and and helps you in better understanding about the formatting of numbers. 
Thanks and Warm Regards,
Harsh
Billions Format - Harsh.pbix (662.3 KB)
https://www.extendoffice.com/documents/excel/3771-excel-format-numbers-in-millions.html