From bitcoin newest source, how can I set transaction fee as more lower?
Some wallet(ledger nano hardware wallet) even provide now custom transaction fee, how is possible?
Actually you are going to set the fee for the transaction if you are using a bitcoin wallet,not an exchange they have their own fixed fee.
So you can set the fee by sat/byte,so if you want to set low fee you can set 1 sat/byte.But you need to be cautious while setting low fee because when the traffic is heavy in the memepool then your transaction will get stuck so you need to aware of the recommended fee before setting your lower fee.