The documents required for WPA ETA License is as follows-
RF Test report from a NABL Accredited lab.
Description of the product.
Receipt of the online fee.
Letter authorizing our experts to file the application on your behalf.
Undertaking that whatever information you've filled in the application is true. It's a type of WPC ETA self-declaration that your product indeed works within the restrictions set by the WPC wing.
Certificate of incorporation of your company
PAN Card of the company