Requirement of amendment in gst registration

Dear Friends,

I am working in the company which is Importer and Trader in Petroleum Products and already have GST registration and now our company start new busness of transportation i.e. GTA Service. Now I need answers to my few queries:

1. Whether we need to make any amendment to our GST registration due to start of new service under the same GST registration.
2. Can I start a new series of Invoice number for the Transportation service i.e. from Invoice No.- July/1/2019-20 for such GTA service only and keep comtinue the Invoice series of sale in trading business running since start from the April, 2019.

Thanks in Advance