research the site first if it is legit, don't join the hyip site that they promise to double your bitcoin in just a short time, and if you want to buy bitcoin in exchange make sure you buy in trusted exchanges like binance or coinbase. Many scammers and hackers nowadays so be aware.
In order for you not to be scammed when investing in bitcoin, you need to research about certain sites so you will know if it is not one of the bitcoin scammers. It's not easy to invest bitcoin without being scammed especially if you are first timer. I've been scammed twice already in some sites. So please before you invest, try to check the reviews if they are reliable or not.