Let me help you in adding the bank's GST number, reeja.
You can add the bank as a supplier so you can add the GST number. Here's how:
Then, for the bank charges, create an expense transaction, then use the newly added supplier (bank) to claim the input tax.
For future reference on how QuickBooks generates reports on GST, you can click this article: The GSTR3B (GSTR 3B) report in QuickBooks.
Let me know if you have other GST questions, I'll be more than willing to help you out.
Create bank as a supplier and then you can enter the GST details. While doing the entries as Expenses you can select the supplier and then GST would be reflected in ITC report.
Let me know if you have any issues
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