Trading journals main purpose is that to identify what goes right and wrong in our trades so that we can learn, improve ourselves. So a trading journals important requirement is that the reason why we taken a particular trade, what happens after taking a trade before the exit (in loss or profits).
Definitely there must be other items like entry price, profit price, stop loss price, underlying price while we take entry incase if we trade in derivatives.
My trading journals consists some other items like whether the entry was at resistance or support , the trend side taken based on whether major/medium/short trend etc.
I prefer trading journal in computer rather than on paper because after few months if i want to verify something, i can just use search option in computer and this won’t be possible incase of paper journal.