The date your Direct Debit is debited from your linked bank account will be considered the contribution date.
For example, if the payment left your bank on 5 April 2025, it would be part of your 2024/25 tax year contribution. This is even if the cash does not arrive into your Freetrade account until 6 April 2025. However, if the payment left your bank on 6 April 6 2025, the payment would be part of your 2025/26 tax year contribution.