Hi,

It is a rare occassion that you will be testing the application without any requirement documents or specifications. Because the Design or the Development part will be done only with the requirement document. From the same document only the test scenarios are identified. You may be asked to do Adhoc testing for an application which the Coding and testing is done without the requirements. In this case you have to test all the available navigational flow, using own logic like by guessing the intended functionality, and the notes followed by the design or development team. While doing Adhoc testing the test scenarios are based on the testers ability to derive more testcases.

If you dont have the clear requirements then you can recheck with the Client or Higher management team to get a clear document until you understand.

Regards,
Ganesan.