Probably the best and easiest option for someone with cash and without too much knowledge is just to buy bitcoin and hold it, anything else will be too risky for someone that does not know what hes doing
Correct , for anyone who doesn't know what they are doing if have lot of money on their wallet it's better to hold it.
While you holding it , you can explore in google about different method for growing your bitcoin and make a step for invest in right place (We don't talk about HYIP nor Ponzi)