enabling bias to my LNA

I have a question about the need for biasing the Vcc pin of the LNA. Exactly how is the bias connection working and why is it needed. What is the biasing element consist of? Not sure of the importance of biasing here.

Please help?

Bias circuit is nedded to stabilize the OP of the transistor against temperature and/or process variations during manufacturing.
Because LNA has probably been optimized just for this OP and this must be maintened all over operating conditions.
Bias element might be simply voltage/current regulator or more complex temperature compensating, process insensitive etc.circuits.

SInce my RF input pin will be connected to the port 1 of my vna is that incoming signal AC in nature?

If it is AC signal signal in nature I want to place a series cap between the input pin of the LNA and the VNA to prevent any DC offset?

If I did not include a series cap between the VNA and input pin of the LNA what is the ramification of the DC offset?

Look at the application note of that IC.There may be a coupling capacitor or not, I don't know.
If there isn't, you should connect a series cap to block the DC level from VNA ouput.This is valid for output too.
Cap values are/might be subjected to frequency of interest and input/output impedances.
Read application note and apply the circuit on your board.