You must be 18 or over, a resident in the UK or a Crown servant (e.g. diplomatic or overseas civil service) or their spouse or civil partner if you do not live in the UK. You cannot hold an IFISA with or on behalf of someone else.
PLEASE REMEMBER, REGARDLESS OF THE TAX BENEFITS, CAPITAL IS AT RISK
Whether investments are held within a IFISA or in a general account, they are not covered by the FSCS; the government backed deposit insurance scheme that protects bank deposits including Cash ISAs.