Junior ISAs were introduced in November 2011 as a replacement to Child Trust Funds. Junior ISAs have the following key features:

• All UK resident children under the age of 18 who do not have a CTF are eligible for Junior ISAs.
• All returns are be tax-free. 
• Both cash and stocks and shares Junior ISAs available. Children are able to hold up to one cash and one stocks and shares Junior ISA at a time (two accounts in total).
• Any person or organisation can make contributions.
• An annual subscription limit of  £9,000 for tax year 2024/25,  which can be split between a cash and a stocks & shares Junior ISAs.
•  There will be no Government contributions into the account. 
• Transfers are permitted between providers, and both ways between cash and stocks and shares Junior ISAs
• Accounts are owned by the child and funds will be locked in until the child turns 18. 
• Children  have the right to manage their accounts from age 16.
• At 16, the child can open an adult cash ISA alongside their Junior ISA
• Junior ISA accounts will by default become adult ISAs on the child's 18th birthday.
• Providers are free to set their own terms and conditions including with regards to minimum contribution limits, charges, and account opening and payment methods that they will accept.

Further information is available on the gov.uk website linked to below

Junior ISAs