what does 元金成長型 mean in the above sentence.
It's a term invented by the financial industry. 元金 means the capital (as opposed to the interest), and 成長型 means the type of financial product is "growth". I.e. a financial product that "attempts to grow your capital".
A similar term is 元金確保型 which normally means it's a more conservative asset allocation.
(This is completely unrelated from the language perspective but be wary of these mutual funds Japanese banks push on you, almost all of them are a terrible deal).