When I paid a Bitcoin bill yesterday to Coinpayments.net (that's what they used), which had no problems, I spotted this text:
Make sure to send enough to cover any coin transaction fees!
What exactly do they mean by this?
I used their bitcoin: hyperlink in Bitcoin Core so I got the "pay form" filled in just as they wanted it, and again, I had zero problems. I just wonder what they could possibly be meaning by this? "Send enough"? Cover "any coin transaction fees"?
Perhaps they meant "don't subtract fees from the amount" That is, if you owe 0.1 BTC and you have 0.1 BTC in you wallet, you shouldn't pay.
Make sure to send enough to cover any coin transaction fees!
This is confusing imo, since the payment is distinct from the transaction fees.
A bitcoin transaction will generally require a network transaction fee to be paid. This payment is awarded to the miner which finds a block that includes said transaction. The fee is implicit: it is simply the sum of all transaction inputs, minus the sum of all transaction outputs (inputs - outputs = fee).
So the payment you send should be for the specified payment amount (in sats), but the transaction you publish will also need to have a suitable fee, such that a miner will include it in an upcoming block. Different wallets will have different user interfaces for how this fee is decided, but in any case it should be distinct from the payment. Do not simply add more BTC to the payment amount, this is not how fees are paid (though this is what the quote above seems to imply).
Your wallet software should deal with the fees distinctly. Usually this is accomplished by allowing you to select a certain 'speed' for the tx (faster = higher feerate), or by allowing you to specify a feerate explicitly (in sats/vbyte, usually), etc.
