Can I make my contribution (BTC) from exchange? or should I use my personal BTC address
You should never use exchange to send any coins to any ICO. Always use your personal wallet.
But sir, there are some ICOs that use coins that can be used for exchange. Example: in the form of ETH or BTC. Which obviously we have to exchange it first.
Of course this is possible but less safe. If you care about your funds I suggest you personal wallet. If some problem will appear it will be easier to solve.