how to get update of my IPAD

Which model of iPad - and from what current version are you attempting to update?

To update from your PC, assuming that your iPad has an available update with which it is compatible, you’ll need to ensure that the latest version of iTunes is installed.

Upon subsequently connecting your iPad to your PC, once recognised, you should see an update button in iTunes.

Here is a description of the procedure:

https://support.apple.com/en-au/HT204204