Cyrpto currency invest is very risky investment platform, Bitcoin or any other altcoin also, if you buy some bitcoin and keep in wallet then it will be secured,I think you should keep always bitcoin in wallet with key password, if you keep in safe then now problem but if you are keeping in exchanges it is very risky, some exchanges are low secured websites and any time can hackers enter it, so better to choose exchange select a good exchange and buy coins, If you want to secure your bitcoin to you have to invest in hardware wallet because hardware wallet is hard to to hack. It needs a physical device to access your wallet. Make sure that your paraphrase key is save in offline or better write it down in a paper and secure it.