Welcome to the Community, @anuraag-biswas.
In QuickBooks Online (QBO), the ability to add a cost centre is currently unavailable. However, the system has a feature called Project, which you can use to track or quickly calculate your cost. This also includes income and profitability.
If you want to know more about this feature, I highly suggest checking out this article: Track income, costs, and profitability by project.
Please let me know if you have any other questions or concerns by leaving a comment below. I'm always here to help. Have a good one!
