A transfer happens when a user moves an asset between two sources that they own.
Both value and price stay the same but the location of the asset changes.
In this case clearly there is no profit/loss generated by the two transactions that made up the transfer.
Example:
Bob owns 5BTC on his Kraken account
Bob decides to move its BTC on a cold wallet for security reasons
Bob balance is still 5BTC but the asset has changed location
Transfers are made up by two separate transactions but linked to each other (one incoming and one outgoing) referring to the same asset, of equal amount and that took place at a very close time.
Example:
Bob withdraws 5BTC from his Kraken account on 20/08/2022 at 3.30pm (withdrawal/outgoing transaction)
Bob deposits 5BTC on his hard wallet on 20/08/2022 at 3.32pm (deposit/ingoing transaction)