Hi Keung C
1. Yes as you have already filed your 2023/24 tax return you do not need to do anything else if no balance to pay.
2. Yes as your Self Assessment closed with the last tax year 2023/24 you do not need to file a 2024/25 tax return unless there is a change in your circumstances and you meet Self Assessment criteria.
3. As your Self Assessment is closed the 2024/25 tax year will be reviewed through your PAYE records. Once reviewed if you have underpaid or overpaid your tax a calculation will be issued.
You can view this online on your personal tax account
Personal tax account: sign in or set up
Thank you