I cannot upgrate my mac retina 2014 model..,what should i do for install..?
I cannot download any application in my mac retina 2014 model lap..,what should i do to install the applications??
You haven't provided many details regarding WHICH application(s) you can't download for your MacBook Pro.
If yours is a 2014 model, then MacOS Big Sur is the latest MacOS you can install. If you're already running this version, then it will not show any update available for it.
This Apple Support article describes what's needed for each version of MacOS: Find out which macOS your Mac is using - Apple Support
You can determine which MacBook Pro model you have by clicking on the Apple menu and choosing About This Mac.
Hope this helps.