There are two ways to make money doing such things, though you can blend the two. Maybe 3 in some cases but that is more facilitation (possibly literally if the police/prosecuting type cares to make it so).
1) You have enough computing power and electrical power that the exchange rate is better than the cost of using them to mine coins/act in the giant computing problem that underpins crypto currencies. Different currencies have different requirements (sometimes by design) for what they need in computing, and how many people are participating to get it done.
2) You bank on the idea that the crypto you either bought or created/mined will be worth more in the future so you buy it now, sell it off at that point in the future and any difference then becomes your profit. In many ways you are some years late for this one.
3) You buy them and sell them on to people you meet in the real world if they are unwilling or unable to do things. Depending upon where you are then this can mean various people ranging from those looking to move some money and dodge fees, those looking to invest, or those looking to dodge the law (at which point you might have just helped them do it and the police come step on your fingers to make you talk).
For the most part crypto is bitcoin and all the rest.
All the rest is four or five coins (ethereum being the one you have most likely heard of) and then a few million more that are likely going nowhere. There may be another in the future (bitcoin has several weaknesses, most of which others aim to address if not otherwise adding new features -- see smart contracts which was ethereum's big trick) but who knows. At the same time the millions going nowhere are often pretty volatile.
https://www.tradingview.com/symbols/BTCUSD/
The wild ride of bitcoin has sort of come to an end (today it is not so far off what it started the year at) but I suppose back in March had you bought in at the low point you would have more than doubled your money had you sold today. The days of hundreds of percent though are way in the past.
Mining. At this point thousands in hardware investment up front and a lot of cheap power is what you need there to join a pool and have anything useful come of it.