There are few options how you can invest your bitcoins.

Here they are:

Bitcoin lending platforms: Bitcoin Lending - Cryptocoinsmania.com
Bitcoin trading sites: Cryptocurrency Trading: The List of Top Trading Sites in 2017
Invest bitcoin into forex, stocks, bonds, indices, etc.: Stocks Trading with Bitcoin: Trade Forex, Stocks, Commodities and More
Bitcoin gambling: Bitcoin Gambling: Top Bitcoin Gambling Sites Reviewed