Can anyone transfer bitcoins into my bank account or do i need to have some bitcoin account for that
You need bitcoin wallet. List of few open source bitcoin wallets: https://bitcoinwallet.guide/
Is it legal to receive bitcoins ? especially in India ?
Why should one take payments in bitcoins ? Is it a good idea or better avoid it ?
Depend on the usecase. Most of the users prefer it because of censorship resistance. Example: WikiLeaks started accepting bitcoin when governments blocked other modes of payment: https://twitter.com/DefendAssange/status/919247873648283653
It’s also a good idea to use bitcoin for payments in a bull market because you save more: https://twitter.com/BtcpayServer/status/1330149166971039750