For better understanding about RF Module .Today we are going to share some brief concept about RF Module. 

What Is An RF Module ? 

An RF module is a separate circuit board that contains all of the circuitry needed to transmit and receive RF energy. It may include an integrated antenna or a connector for an external antenna. RF modules are typically integrated into a larger embedded system to add wireless communication functionality. Most implementations include transmit and receive.
Two of the most widely used RF modules are bluetooth modules and wifi modules. But, almost any transmitter can be a wireless module.

Does RF module needs shielding cover? 

RF Module Shielding
RF Module shieldingThe radio elements of the transmitter must be shielded. There are a few parts that are permitted to be external to the shield such as PCB antenna and tuning capacitors. But for the most part, all components associated with your transmitter should be housed beneath a shield.

If for module to get RF certification, I think module need to add shielding case according to regulation require.
If use module on the system, it may not need the cover. It's depending on the test result.

Feasycom RF module

Feasycom Shielding cover module
FSC-BT616, FSC-BT630, FSC-BT901,FSC-BT906,FSC-BT909,FSC-BT802,FSC-BT806

Feasycom Non-Shielding cover module
FSC-BT826,FSC-BT836, FSC-BT641,FSC-BT646,FSC-BT671,FSC-BT803,FSC-BW226