inter state delivery

Yes, you can issue such an invoice.

Where goods are delivered by the supplier to the recipient but at the instruction of a third person (i.e., the person providing instructions to the supplier on where the delivery should take place), then the place of supply will be the principal place of business of such third party and not of the actual recipient. Sec. 10(1)(b) of IGST Act.

So, CGST+SGST will be payable by you.

Issue Invoice/EWB under ‘Bill To-Ship To’ mode.

In such transactions two supplied are involved. Your role as a supplier is restricted to first part only.

Bill to: Details of registered buyer. He will get the ITC.

Ship To: Details of unregistered recipient in other state.

Whether transfer of goods to another branch located outside the State is taxable? 
Ans. In terms of Section 25(4) of the CGST Act, 2017, every person who is required to obtain 
separate registration for every branch located in different State or Union territory shall 
be treated as distinct persons. Accordingly, the supply of goods (stock transfers) to a 
branch located outside the State would qualify as supply, liable to tax in terms of 
clause 2 to Schedule I of the CGST Act, 2017. Further, it is important to note that, 
supply of goods to a branch/ unit located within the same State having separate 
registration would also be liable to tax since both such units (supplying unit and 
recipient unit) would qualify as distinct person in terms of Section 25(4).

Please note that the earlier reply was made by assuming the recipient as unregistered recipient in other state where your buyer wants you to deliver directly. The recipient wasn’t assumed as a branch.