am a beginner ..so can someone suggest me good exchange to buy ERC20?
I personally recommend bittrex or cryptopia, these are the only exchanges I use and consider them to be user friendly and safe to use than most exchanges. They are also secure since you are able to configure two factor authenticator which means that your account cannot easily get hacked. Withdrawals and deposits are easy to make and faster depending on which currency is being withdrawn or deposited. These are the only two exchanges I recommend for best trading experience.