The first way of investing in bitcoin is through learning,  might look abstract as there's no physical asset attached but u have what you need as a beginner step to dive into Bitcoin investment, sometimes you need to understand where on the chain structure to get into investment  . Learning  will give you a solid  knowledge on what you are do as a Bitcoin investor. 
Talking about having a physical assets , then you should know that investment in BTC might not be a real physical  asset but a virtual one inform of figures. Currently, the most confidential form of investment (as of now) is BTC but even we are confident we have to prepare fore the bad side , bitcoin is not just any kind of coin though so at worst there's should be a little profit in accordance to your Capital.

Enough of the long talking , you want to invest  then consider buying anf holding BTC for a long period of time, all you have to do is have a wallet and purchase a decent amount of BTC either at once or you can DCA over the period to accumuate a targ3t point for your investment