What should I do with $20k? Invest or put into savings plan?

Hi all, I have about $20,000 that I would like to put away somewhere that can give me the best or safest rates. I will not need this sum of money in the next few years. I have not invested before but am very much looking to put this money somewhere that can grow. I would prefer to be able to one shot use all the money and not be bought into a plan that is paid monthly. I have talked to a financial agent but I’m not too sure if what she has is truly what I want. Thanks heaps.