Bitcoin Core What default values should I pass for some positional RPC params in sendtoaddress
The fee estimator works by targeting the number of blocks that will occur between the time when you broadcast and when it confirms. So a confirmation target of 6 would mean that the fee estimator is trying to get your transaction confirmed within 6 blocks. The fee estimator does not know within how many blocks you want your transaction to be confirmed, so it asks you as a parameter.

The default value for this is 6, but you can set it to whatever you want.