So in addition to  what you just said above, one of the safest wallet newbies could store their Bitcoin for maximum security are non custodial wallets such as "Electrum" and "BlueWallet", as you gives you the privilege to own the private key of your wallet. Whereas, another way to buy Bitcoin with fiat money is simply by using a Bitcoin A.T.M in places where such is available, because though Bitcoin A.T.Ms are not common in all the countries, it's also one of the reliable means of buying Bitcoin with fiat.