If you are looking for scam and ponzi sites where you can double your interests, they are everywhere, and they know how to do that without stress, and that is not an advice for you to accept. The price of bitcoin is rising since this year very fast, therefore, I will advice you to place your bitcoin into a wallet that is safe and secured and wait for the price of bitcoin to keep rising, and at that time, you can get profits from the rise in its price.
If you are a trader, trade with it, otherwise, leave it in the wallet, as an investment with commissions growing.
Coinbase is one good wallet to use, as it is one I use it and it has good rating.