Question 51:-
Individual person is registered under GST and engaged in business of providing software designing service to USA based company ,i.e. ( non Taxable Terriority) . What is GST applicability , Export of services OR under Reverse Charge.

Answer

As per section 16 of IGST Act, Zero rated supply includes supply of goods or services or both. You can export any service under LUT without payment of IGST or can export the service on payment of IGST and claim refund of IGST paid on completion of export. 
We would like to point out that the export of service is subject to condition given in section 2 (6) of IGST ACt same is reproduced below
6) 'export of services' means the supply of any service when,''
(i) the supplier of service is located in India;
(ii) the recipient of service is located outside India;
      (iii) the place of supply of service is outside India;
(iv) the payment for such service has been received by the supplier of service in convertible foreign exchange; and
(v) the supplier of service and the recipient of service are not merely establishments of a distinct person in accordance with Explanation 1 in section 8;
From the fact given in your question your service is covered under definition of 'online information and database access or retrieval services' 
in section 2 of IGST Act , which is reproduced below:-
'online information and database access or retrieval services' means services whose delivery is mediated by information technology over the internet or an electronic network and the nature of which renders their supply essentially automated and involving minimal human intervention and impossible to ensure in the absence of information technology and includes electronic services such as,''
(i) advertising on the internet;
(ii) providing cloud services;
(iii) provision of e-books, movie, music, software and other intangibles through telecommunication networks or internet;
(iv) providing data or information, retrievable or otherwise, to any person in electronic form through a computer network;
(v) online supplies of digital content (movies, television shows, music and the like);
(vi) digital data storage; and
(vii) online gaming;
Further as per Section 13(12) Place of supply in your case is USA. Section 13(12) is reproduced below:-
SECTION 13 of IGST Act
(12) The place of supply of online information and database access or retrieval services shall be the location of the recipient of services.
Thus, In our opinion if you are fulfilling all the above said conditions then your supply is Export of service and there is no reverse charge on the same in GST.
In case you are having any other situation in mind, please elaborate so that we may provide adequate answer. (Reply dt. 24/4/2018)