in QBO, 1 account is for 1 company file 

https://quickbooks.grsm.io/India

If you want to manage multi company files, consider using QB Desktop US version with a one time license. For Pro 1 user, you may purchase it for $300 directly, or around $200 thru a partner/reseller.

Hi Rajat,

Welcome to QuickBooks Community.

Currently, QuickBooks Online can only handle one company profile per subscription. If you have multiple companies, you'll have to sign up for once QuickBooks Online account per company.

I hope this helps.