The ISA allowance is the maximum amount of how much you can put in an ISA per tax year. The maximum ISA allowance is £20,000, of which £4,000 can be paid into a lifetime ISA.
You can split your Individual Savings Account (ISA) allowance however you like, across different ISA types, including cash ISAs, innovative finance ISAs and stocks and shares ISAs. There’s no Income Tax or Capital Gains Tax (CGT) to pay on any gains from ISA investments, so you won’t get taxed on the interest.
As of April 2024, you can also pay into more than one of each ISA type in a tax year. In previous years for example, you wouldn’t have been able to pay into multiple cash ISAs within the same tax year, but now you can.
Keep in mind that the allowance resets at the end of each tax year, which is the 5th April 2025.