How to use the call menu in skype?

The Call menu enables you to manage your calls. If the Call menu appears grayed out, you are not actively engaged in any calls on Skype. While you are actually on a Skype call, or receiving an incoming call, the menu is no longer grayed out.
The following options are available from the Call menu.

Answer
You can answer an incoming call from the menu, but it is probably easier to click the green call button that is displayed with incoming calls.

Ignore
This option lets you ignore an incoming call so that you won’t hear it ring and can continue your activities without interruption.

Resume
You can place a call on hold; Resume enables you to resume the call.

Hold
You can place a call on hold and answer an incoming call if you happen to already be talking to someone on Skype and receive a call from someone else.

Mute/Unmute Microphone
During a call, you can select Mute Microphone. When you do, your microphone stops sending sound to the audio-in device. While the microphone is muted, the Mute microphone option changes to Unmute microphone.

Hang Up
At any time during a call, you can click the red hang up button to end the call. All the items available from the Call menu are generally available to you by clicking various Skype buttons and toolbar icons. Unless you need to navigate the Call menu for these options, you may find clicking a visible button to be easier and more convenient.