GST: How can someone take input tax credit on bank charges?

A statement issued by a bank can be treated as a tax invoice, according to GST law

There is a party A in a foreign country that wants to market its products in India. We represent party A in India and help them in marketing and other support activities in India. We help them in getting orders from party B in India. Party A remits us commission in foreign currency, converted into rupees and given to us by our banks. Please clarify if we need to get registered under the goods and services tax (GST) and pay tax under the reverse charge mechanism (RCM) or any other head or not. If tax is payable, what will be