GSTR-6 is a return filed by Input Service Distributors (ISDs) to distribute the input tax credit (ITC) to their respective branches or units that have made the payment on the input supplies. Here's how to file GSTR-6 return:

Log in to the GST portal using your valid credentials.

Go to the 'Returns' tab on the dashboard and select the financial year and return filing period for which you want to file GSTR-6.

Click on the 'Prepare Online' button to fill out the return.

Fill out the details of the inward supplies received and the ITC availed in the appropriate tables.

Reconcile the ITC claimed with the ITC available in the electronic credit ledger.

Verify the return using a Digital Signature Certificate (DSC) or an Electronic Verification Code (EVC).

After verification, click on the 'Submit' button.

The taxpayer will receive an acknowledgement receipt of the submitted return.

It is important to note that GSTR-6 must be filed by the 13th of the following month for which the return is being filed. Additionally, ISDs must ensure that the input tax credit is distributed to their respective branches or units in proportion to the turnover of the branches or units. Failure to file GSTR-6 on time or any discrepancies in the input tax credit distribution may result in penalty and interest. Therefore, it is advisable to seek professional help if necessary to ensure compliance with GST regulations.