Can someone please tell me that how to update adobe flash
You can't. The Flash Player reached its End of Life and Adobe recommends to fully uninstall the plugin.
Please check out the following page for more information:
so how can i watch films and videos normally?
The same as everyone else does. Go to YouTube, Vimeo or your favorite online Streaming channel.
Nobody uses Flash videos anymore, not since browsers started supporting HTML5 videos without 3rd party players or plugins.
Flash Player is end of life and no longer available except for enterprises who have a special arrangement with Harman. See link below.
Hope that helps.