Crypto trading is legal but holding crypto in physical or any other form is illegal as one can face huge tax implications if holding in physical or any other form. You can check Youtube videos & search on internet. This can help u.
Currently crypto currency is major discussion going on, few countries are against these & few countries are with it as they are virtual currencies. It is big discussion everywhere & one can invest / trade if they r capable to take high risk & are high risk currencies than equity / commodities. In a fraction of seconds price changes. It all depends on news, tweet, economy & many more things. Their calculation are more complex than other things. U might find shows on TV about it on news channel & can search on internet. One who has knowledge about it can understand in detail & can trade invest in it, one without knowledge trades or invest might lose their money without knowing about a currency.
You need to research on ur own & take ur own deceision about it. As stock brokers are there, you will find crypto brokers offering investment in cryptocurrency. Like wazirx, zebpay, coinswitch kuber in India, binance, coindcx, & many others r there.
This is good that u posted & may others want to know more about this.