If i have iphone with the version of 3.2.1 could i get ios 4.3 install?

If i have iphone with the version of 3.2.1 could i get ios 4.3 install?

I depends what iPhone you have.
just plug it into iTunes, and it will tell you what the latest supported iOS will be for that phone.

It depends which iPhone it is. As long as its iPhone 3GS or above then yes.

First, find out your model.
If you have an iPhone 3G (not S) then your max iOS is 4.2.1
If you're still looking for compatible app to use see these,
https://sites.google.com/site/appleclubfhs/support/advice-and-articles/finding-apps-for-older-devices
or
https://itunes.apple.com/...?mt=8&uo=4