Itc for ecommrce commission

Ad per section 16, if input service is used in the course or furtherance of business, then itc in respect of such service shall be available to the taxable person.
Therefore, if such commission is paid for supply of taxable goods then input tax credit with respect to such commission can be availed.
Also, such input tax credit needs to be shown like other input tax credit in gstr 3b

Yes u can avail input on commsion invoice from E-commerce operator , & plz deduct TDS (income tax) on amount before gst