in case of proprietorship firm, the proprietor to whom authorise for gst migration, if he wants not to authorise any body
While filling the details in Promoters/ Partners tab, there would be question in the last (ALSO AUTHORIZED SIGNATORY) and YES would be selected as default. In that case, there is no need to fill the details in next tab which is Authorized Signatory tab, system will automatically pick the proprietor details in that tab.
But, if you wish to change that to NO, then you will have to fill details of authorized signatory in next tab i.e. Authorized Signatory tab and will have to attach the authority letter issued by Proprietor.