I've been asked by my friends and family if the bitcoin companies make its trading, how does it do?! really don't know what to say.. all I know is I invested, already earned the capital and now the profit.
Yes there are companies that do trades - these are often called exchanges it most of them work with buy and sell orders. So we as users send our bitcoins to the exchanges and then since bitcoin is in the exchange system (so they can move it and do what they want with it) they give you an "imaginary" thing that you own bitcoins in fact your bitcoins are stored in some wallet of a particular exchange but balances and trades are recorded on the database of an exchange. When you want to withdraw your bitcoins then exchange will release coins to your desired address. Basically for trading you can look at it like trading stocks or some other asset in some sort, since you really don't need to understand how does it work - but keeping bitcoins on an exchange is not the option either tho since you need to trust the exchange that they don't run with your money.
But again as other said bitcoin doesn't have any central authority thats why if you lose your coins you lsoe them forever you can't ask anybody to reset your "account" as you can with PayPal for instance.
If you are looking to understand how does it work I'd recommend this free udemy course as it explains a lot:
https://www.udemy.com/one-month-bitcoin/Best is to ask more questions if you are not certain about other things, we are here to help you.
Be aware of SCAMS because there are many of them around since there are no refunds!
