I was recently studying this question and here is what I found:
- You can use Coinbase if you are in US and you will feel pain because of their fricking commissions
- You can use some exchanges like Bitfinex, Bittrex and some others but still the rate would be awful
- You can use new platforms like Cryptology and some others but there is no information on them atm but there might be the better rate
- You can use LocalBitcoins (which is banned in Russia)
What is your choice?
The best one according to me right now is using Bitcoin ATMs. they have quite high fees but they ensure privacy. alternatively you can use Localethereum. I think Localbitcoins started requiring KYC