RE: How to test Token Based Authentication of Get operation to find any record like Sales order/invoice?
The answer tends to be language specific. Without knowing more about what you are using or have tried, I say try using Postman.
https://blog.zuar.com/netsuite-api-exploring-soap/ has a reasonable example on how to use Postman for this purpose. Expect to get into more advanced features of Postman if you wish to use it with SuiteTalk Soap webservices.