Simple project feasibility

Here is what I want to do with Arduino. Connect up RF transmitter to Arduino pcb. Trigger the transmitter via an android app to send appropriate RF to receiver.

Very straightforward just want confirmation it is feasible before even starting. Have tracked down RF transmitter/receiver PCBs for peanuts, couple of questions.

Which Arduino hardware module would you recommend initially? Functionality will be limited to what I have stated above at least initially but if there is more flexible choice of module to add functionality at a later date please recommend.

I am a software developer using Java, C++, C#. Where do I start communicating from android to Arduino?

Many thanks

Edit. Incidentally I need wireless communication between android and Arduino project. Do I need a Wi-Fi module, Bluetooth module to plug into Arduino for communication? Prefer a Wi-Fi presumably sending HTTP packets or something similar? Thanks again

The first question to answer is what is the range required. That will have a large effect on the choice of wireless method.

For RF output? 20 m? The more the better I guess. I was looking at these:

But can't instantly see the range

Thanks for your reply

Well it says 90 m in an open range but couple of users supported 6 m only but that could be an antenna problem. Any idea on my other questions?