Conversion to Quick release I am pretty new to bicycles and have a query regarding my Giant Contend 3. 

The bolts on my wheels looks like in the picture, how can i convert them to quick release and what components would be required for same?

Sorry if this question has been asked before.
That might be a security bolt - although the photo is unclear. Are you sure the bike wasn't stolen? The previous owner should have had the matching 'key' for the security bolt. If you don't have the key (and have made sure your bike isn't stolen by checking the stolen bike indexes), you can remove the security bolt by using  brute force (grinder, dremel, vice grips, jamming an allen key into it, etc.). These are usually destructive processes.

Otherwise, if it's just an allen (hex) nut, you can remove it with an allen key / hex driver. Your local bike or hardware store should have one that fits.

Once you get it off, replacement quick releases are easily purchased at your bike store or online. You could even replace it with your own security skewer such as a PitLock, for which you'd have the key.

If it were me, though, I'd keep the hex bolt as is and just get a $10-15 bike multitool that has the right size hex. The hex provides a modicum of security (especially if you fill it with a ball bearing/wax) and makes it a smidge harder for bike thieves to make of with. It'll just add a few more seconds to changing your tire but will prevent casual theft.