There are 3 major antivirus software out there: Bitdefender, AVG and Kaspersky.
Each of these sit quietly near your clock in the taskbar and can be identified via the icon they have.
This is Kaspersky
This is AVG
This is BitDefender
Kaspersky Version
Open the main program window.
In the bottom left part of the window click the Support link.
The version number (for example, 13.0.2.558) is displayed in the Support window in the Application version string.
AVG Version
Run AVG.
Click Support in the top right corner.
Switch to the Product tab.
Copy the information as marked in red on the picture below.
BitDefender Version
Run BitDefender
Find the application title window.
The name of the application is your BitDefender version.