Bills issued without gst

First of all As per the defination of Agrregate Turnover u//s 2(6) means Value all taxable,Exempted,& export supplies of goods or services of person under same PAN number .


So if you have obtain registration for one firm the turnover under unregistered firm is also required to included under the registered firm .
So if the Unregistered firm is another state then obtain the registration for the same. If it is in same state then then the supplies made under same need to be included in registered firm or you can obtain separate registration for it under same state also.

Bills can be issued without gst.
read sec 22 of cgst act.