I usually add notes to transactions as they come in, so I don’t forget what it was for.
With connected bank/card accounts, it’s currently not possible to add a note while the transaction is pending. Sometimes this takes a while. It would be great if it was possible!
I would really appreciate this being added as a feature too. It is really annoying to have to wait for a transaction to come through properly before being able to categorise it and add notes to it. I use these functionalities in a similar in order to keep track of different types of spending and it is particularly useful when travelling and taking out cash.