The maximum amount you can pay into a JISA in the current tax year is £9,000 per JISA. Contributions into a JISA don’t count towards your own ISA allowance of £20,000 per tax year.
The minimum amount you can pay into a Moneybox Junior ISA is £1. If you are making an instant bank transfer, the minimum payment is £100.
Please note that any contributions into a Junior ISA will be considered a gift, and as such, cannot be repaid if you change your mind. JISA funds can only be withdrawn by the child once they turn 18.