How to update apps on Android from Playstore? Is it possible to update apps that is on my android from a PC????

I do not see any option from Playstore to update apps. And now am not able to use Whats app as i wasnt able to download the latest version. Do somebody have an advice for this??
There is no way to push the update out from the play store when done from the PC. Sometimes if you click "install" for the app, it may allow you to select the android device as the target, even though it is already installed, but this is rare.

There are ways to download the APK using the PC then sideload onto the device.

The best way to update apps is to start the play store on the device, choose "my apps", then perform whatever updates are presented.