Reporting server for Azure webapp

which reporting server?

 

if you see in azure portal, it provides you following inbult for ready to use purpose:

 

however, if your software is not mentioned here, you can go for your own Virtual Machine (VM), and once you have your own VM on that you can install anything you want, just like your own PC.

 

I suggest you contact Azure Support for this, they will give you best solution.