yes,You can use residential rent agreement (If rented) or scanned copies of original documents or electricity bill or Municipal Tax khata copy in your name (if Owned) as address proof for GST Registration but make sure that its your place of business. Because OFFICER may come to visit after registration also. If he do not find any business activity, you may be get in trouble. Do follow rules like GST number display at prominent place etc. If you are taking registration on residential address and running business on different address then please add that address as additional place of business otherwise you may get in more trouble.